small lcd panel meter free sample

To put it simply we are a small company and do not have the resources to test every single part, so we list every thing as hazardous. Please recycle all electronic parts responsibly and under no circumstance eat, drink or smoke these parts and wash your hands after touching!

To put it simply we are a small company and do not have the resources to test every single part, so we list every thing as hazardous. Please recycle all electronic parts responsibly and under no circumstance eat, drink or smoke these parts and wash your hands after touching!

The Simpson M235 Mini-Max LCD Digital Panel Meter for DC voltage uses a 3.5-digit LCD display for increased readability. The screw terminals allow for easy mounting, while the mounting bracket lets you stack multiple meters for convenience.

The meter is designed for lab-grade pH measurement in the field with a variety of intelligent functions in a rugged body, suitable for small-volume or test tube measurement with the help of the LabSen 243-6 pH/Temp. semi-micro electrode.

The meter is designed for lab-grade pH measurement in the field with a variety of intelligent functions in a rugged body, suitable for small-volume or test tube measurement with the help of the LabSen 243-6 pH/Temp. semi-micro electrode.

The Series SPPM2 Graphical User Interface Panel Meter is a configurable, full-color 4.3" (109 mm) touch screen display that can be used in a variety of applications. By using the free Windows® based Interface Panel Design Studio software, users can personalize the display with buttons, switches, and analog and digital scales to suit their needs. A development kit is also available, which includes a development board with buttons, dials, LEDs, and screw terminals to test the functionality of all inputs and outputs.

Besides the above four CGMs, other meters are being developed that do not require blood samples. One such CGM is called GlucoTrack by Integrity Applications, which measures blood glucose via your earlobe. However, it hasn’t yet been FDA approved.

a line of extreme and ultra-narrow bezel LCD displays that provides a video wall solution for demanding requirements of 24x7 mission-critical applications and high ambient light environments

The Contour Next EZ blood glucose monitor needs just a small sample size of blood and features settings which allows you to personalize in order to best fit your preferences. The meter also has an easy-to-read display and Second-Chance Sampling which allows you to apply more blood which may help prevent wasting test strips and may help to save money.

‡ Medicare coverage is available for FreeStyle Libre 14 day systems for cell phone use if FreeStyle LibreLink is used in conjunction with the FreeStyle Libre 14 day readers. Patients must meet Medicare eligibility coverage criteria LCD L33822 (July 2021). Local Coverage Article: Glucose Monitor Policy Article (A52464), July 2021.

** The LibreView data management software is intended for use by both patients and healthcare professionals to assist people with diabetes and their healthcare professionals in the review, analysis and evaluation of historical glucose meter data to support effective diabetes management. The LibreView software is not intended to provide treatment decisions or to be used as a substitute for professional healthcare advice.

An electricity meter, electric meter, electrical meter, energy meter, or kilowatt-hour meter is a device that measures the amount of electric energy consumed by a residence, a business, or an electrically powered device.

Electric utilities use electric meters installed at customers" premises for billing and monitoring purposes. They are typically calibrated in billing units, the most common one being the kilowatt hour (kWh). They are usually read once each billing period.

When energy savings during certain periods are desired, some meters may measure demand, the maximum use of power in some interval. "Time of day" metering allows electric rates to be changed during a day, to record usage during peak high-cost periods and off-peak, lower-cost, periods. Also, in some areas meters have relays for demand response load shedding during peak load periods.

As commercial use of electric energy spread in the 1880s, it became increasingly important that an electric energy meter, similar to the then existing gas meters, was required to properly bill customers, instead of billing for a fixed number of lamps per month.

DC meters measured charge in ampere hours. Since the voltage of the supply should remain substantially constant, the reading of the meter was proportional to actual energy consumed. For example, if a meter recorded that 100 ampere hours had been consumed on a 200-volt supply, then 20 kilowatt-hours of energy had been supplied.

Many experimental types of meter were developed. Thomas Edison at first worked on a direct current (DC) electromechanical meter with a direct reading register, but instead developed an electrochemical metering system, which used an electrolytic cell to totalise current consumption. At periodic intervals the plates were removed and weighed, and the customer billed. The electrochemical meter was labor-intensive to read and not well received by customers.

An early type of electrochemical meter used in the United Kingdom was the "Reason" meter. This consisted of a vertically mounted glass structure with a mercury reservoir at the top of the meter. As current was drawn from the supply, electrochemical action transferred the mercury to the bottom of the column. Like all other DC meters, it recorded ampere hours. Once the mercury pool was exhausted, the meter became an open circuit. It was therefore necessary for the consumer to pay for a further supply of electricity, whereupon, the supplier"s agent would unlock the meter from its mounting and invert it restoring the mercury to the reservoir and the supply. In practice the consumer would get the supply company"s agent in before the supply ran out and pay only for the charge consumed as read from the scale. The agent would then reset the meter to zero by inverting it.

In 1885 Ferranti offered a mercury motor meter with a register similar to gas meters; this had the advantage that the consumer could easily read the meter and verify consumption.DC meter by Dr Hermann Aron, who patented it in 1883. Hugo Hirst of the British General Electric Company introduced it commercially into Great Britain from 1888.

The first specimen of the AC kilowatt-hour meter produced on the basis of Hungarian Ottó Bláthy"s patent and named after him was presented by the Ganz Works at the Frankfurt Fair in the autumn of 1889, and the first induction kilowatt-hour meter was already marketed by the factory at the end of the same year. These were the first alternating-current watt-hour meters, known by the name of Bláthy-meters.Elihu Thomson of the American General Electric company developed a recording watt meter (watt-hour meter) based on an ironless commutator motor. This meter overcame the disadvantages of the electrochemical type and could operate on either alternating or direct current.

Panel-mounted solid state electricity meter, connected to a 2 MVA electricity substation. Remote current and voltage sensors can be read and programmed remotely by modem and locally by infrared. The circle with two dots is the infrared port. Tamper-evident seals can be seen

The most common unit of measurement on the electricity meter is the kilowatt hour [kWh], which is equal to the amount of energy used by a load of one kilowatt over a period of one hour, or 3,600,000 joules. Some electricity companies use the SI megajoule instead.

In addition to metering based on the amount of energy used, other types of metering are available. Meters which measured the amount of charge (coulombs) used, known as ampere hour meters, were used in the early days of electrification. These were dependent upon the supply voltage remaining constant for accurate measurement of energy usage, which was not a likely circumstance with most supplies. The most common application was in relation to special-purpose meters to monitor charge / discharge status of large batteries. Some meters measured only the length of time for which charge flowed, with no measurement of the magnitude of voltage or current being made. These are only suited for constant-load applications and are rarely used today.

Mechanism of electromechanical induction meter. 1: Voltage coil: many turns of fine wire encased in plastic, connected in parallel with load. 2: Current coil: three turns of thick wire, connected in series with load. 3: Stator: concentrates and confines magnetic field. 4: Aluminum rotor disc. 5: rotor brake magnets. 6: spindle with worm gear. 7: display dials: the 1/10, 10 and 1000 dials rotate clockwise while the 1, 100 and 10000 dials rotate counterclockwise

Electricity meters operate by continuously measuring the instantaneous voltage (volts) and current (amperes) to give energy used (in joules, kilowatt-hours etc.). Meters for smaller services (such as small residential customers) can be connected directly in-line between source and customer. For larger loads, more than about 200 ampere of load, current transformers are used, so that the meter can be located somewhere other than in line with the service conductors. The meters fall into two basic categories, electromechanical and electronic.

On a single-phase AC supply, the electromechanical induction meter operates through electromagnetic induction by counting the revolutions of a non-magnetic, but electrically conductive, metal disc which is made to rotate at a speed proportional to the power passing through the meter. The number of revolutions is thus proportional to the energy usage. The voltage coil consumes a small and relatively constant amount of power, typically around 2 watts which is not registered on the meter. The current coil similarly consumes a small amount of power in proportion to the square of the current flowing through it, typically up to a couple of watts at full load, which is registered on the meter.

The disc is acted upon by two sets of induction coils, which form, in effect, a two phase linear induction motor. One coil is connected in such a way that it produces a magnetic flux in proportion to the voltage and the other produces a magnetic flux in proportion to the current. The field of the voltage coil is delayed by 90 degrees, due to the coil"s inductive nature, and calibrated using a lag coil.eddy currents in the disc and the effect is such that a force is exerted on the disc in proportion to the product of the instantaneous current and instantaneous voltage. A permanent magnet acts as an eddy current brake, exerting an opposing force proportional to the speed of rotation of the disc. The equilibrium between these two opposing forces results in the disc rotating at a speed proportional to the power or rate of energy usage. The disc drives a register mechanism which counts revolutions, much like the odometer in a car, in order to render a measurement of the total energy used.

The disc is supported by a spindle which has a worm gear which drives the register. The register is a series of dials which record the amount of energy used. The dials may be of the cyclometer type, an odometer-like display that is easy to read where for each dial a single digit is shown through a window in the face of the meter, or of the pointer type where a pointer indicates each digit. With the dial pointer type, adjacent pointers generally rotate in opposite directions due to the gearing mechanism.

Most domestic electricity meters must be read manually, whether by a representative of the power company or by the customer. Where the customer reads the meter, the reading may be supplied to the power company by telephone, post or over the internet. The electricity company will normally require a visit by a company representative at least annually in order to verify customer-supplied readings and to make a basic safety check of the meter.

In an induction type meter, creep is a phenomenon that can adversely affect accuracy, that occurs when the meter disc rotates continuously with potential applied and the load terminals open circuited. A test for error due to creep is called a creep test.

Electronic meters display the energy used on an LCD or LED display, and some can also transmit readings to remote places. In addition to measuring energy used, electronic meters can also record other parameters of the load and supply such as instantaneous and maximum rate of usage demands, voltages, power factor and reactive power used etc. They can also support time-of-day billing, for example, recording the amount of energy used during on-peak and off-peak hours.

The meter has a power supply, a metering engine, a processing and communication engine (i.e. a microcontroller), and other add-on modules such as a real time clock (RTC), a liquid crystal display, infra red communication ports/modules and so on.

The metering engine is given the voltage and current inputs and has a voltage reference, samplers and quantisers followed by an analog to digital conversion section to yield the digitised equivalents of all the inputs. These inputs are then processed using a digital signal processor to calculate the various metering parameters.

The largest source of long-term errors in the meter is drift in the preamp, followed by the precision of the voltage reference. Both of these vary with temperature as well, and vary wildly when meters are outdoors. Characterising and compensating for these is a major part of meter design.

The processing and communication section has the responsibility of calculating the various derived quantities from the digital values generated by the metering engine. This also has the responsibility of communication using various protocols and interface with other addon modules connected as slaves to it.

RTC and other add-on modules are attached as slaves to the processing and communication section for various input/output functions. On a modern meter most if not all of this will be implemented inside the microprocessor, such as the RTC, LCD controller, temperature sensor, memory and analog to digital converters.

Remote meter reading is a practical example of telemetry. It saves the cost of a human meter reader and the resulting mistakes, but it also allows more measurements, and remote provisioning. Many smart meters now include a switch to interrupt or restore service.

A KYZ interface is a Form C contact supplied from the meter. In a KYZ interface, the Y and Z wires are switch contacts, shorted to K for a measured amount of energy. When one contact closes the other opens to provide count accuracy security.

The KYZ relay generates pulses. The term KYZ refers to the contact designations: K for common, Y for Normally Open, and Z for Normally Closed. When incorporated into an electrical meter, the relay changes state with each full or half rotation of the meter disc. Each state change is called a "pulse." When connected to external equipment, rate of use (kW) as well as total usage (kWh) can be determined from the rate and number of pulses.

KYZ outputs are also the classic way of attaching electricity meters to programmable logic controllers, HVACs or other control systems. Some modern meters also supply a contact closure that warns when the meter detects a demand near a higher electricity tariff, to improve demand side management.

Some meters have an open collector or IR LED output that give 32-100 ms pulses for each metered amount of electrical energy, usually 1000-10000 pulses per kWh. Output is limited to max 27 V DC and 27 mA DC. These S0-outputs usually follow the DIN 43864 standard.

Many meters designed for semi-automated reading have a serial port that communicates by infrared LED through the faceplate of the meter. In some multi-unit buildings, a similar protocol is used, but in a wired bus using a serial current loop to connect all the meters to a single plug. The plug is often near a more easily accessible point.

In the European Union, the most common infrared and protocol is "FLAG", a simplified subset of mode C of IEC 61107. In the United States and Canada, the favoured infrared protocol is ANSI C12.18. Some industrial meters use a protocol for programmable logic controllers (Modbus or DNP3).

One protocol proposed for this purpose is DLMS/COSEM which can operate over any medium, including serial ports. The data can be transmitted by Zigbee, Wi-Fi, telephone lines or over the power lines themselves. Some meters can be read over the internet. Other more modern protocols are also becoming widely used, like OSGP (Open Smart Grid Protocol).

Electronic meters now use low-power radio, GSM, GPRS, Bluetooth, IrDA, as well as RS-485 wired link. The meters can store the entire usage profiles with timestamps and relay them at the click of a button. The demand readings stored with the profiles accurately indicate the load requirements of the customer. This load profile data is processed at the utilities for billing and planning purposes.

AMR (Automatic Meter Reading) and RMR (Remote Meter Reading) describe various systems that allow meters to be checked remotely, without the need to send a meter reader. An electronic meter can transmit its readings by telephone line or radio to a central billing office.

Large commercial and industrial premises may use electronic meters which record power usage in blocks of half an hour or less. This is because most electricity grids have demand surges throughout the day, and the power company may wish to give price incentives to large customers to reduce demand at these times. These demand surges often correspond to meal times or, famously, to advertisements interrupting popular television programmes.

A study using a consumer-readable meter in 500 Ontario homes by Hydro One subsequently offered free power monitors to 30,000 customers based on the success of the pilot.Google PowerMeter, take information from a smart meter and make it more readily available to users to help encourage conservation.

Plug-in electricity meters (or plug load meters) measure energy used by individual appliances. There are a variety of models available on the market today but they all work on the same basic principle. The meter is plugged into an outlet, and the appliance to be measured is plugged into the meter. Such meters can help in energy conservation by identifying major energy users, or devices that consume excessive standby power. Web resources can also be used, if an estimate of the power consumption is enough for the research purposes. A power meter can often be borrowed from the local power authorities

Domestic variable-rate meters generally permit two to three tariffs ("peak", "off-peak" and "shoulder") and in such installations a simple electromechanical time switch may be used. Historically, these have often been used in conjunction with electrical storage heaters or hot water storage systems.

Radio-activated switching is common in the UK, with a nightly data signal sent within the longwave carrier of BBC Radio 4, 198 kHz. The time of off-peak charging is usually seven hours between midnight and 7:00am GMT/BST, and this is designed to power storage heaters and immersion heaters. In the UK, such tariffs are typically branded White Meter or Dual-Rate. The popularity of such tariffs has declined in recent years, at least in the domestic market, because of the (perceived or real) deficiencies of storage heaters and the comparatively much lower cost of natural gas per kWh (typically a factor of 3-5 times lower). Nevertheless, a sizeable number of properties do not have the option of gas, with many in rural areas being outside the gas supply network, and others being expensive upfront to upgrade to a radiator system.

An Economy 10 meter is also available, which gives 10 hours of cheap off-peak electricity spread out over three timeslots throughout a 24-hour period. This allows multiple top-up boosts to storage heaters, or a good spread of times to run a wet electric heating system on a cheaper electricity rate.

Most meters using Economy 7 costs are 21.34p per kWh during the peak usage period with 7.83p per kWh during the off-peak usage period, and a standing charge of 18.90p per day.washing machines, tumble dryers, dishwashers and immersion heaters may be set so that they only switch on during the off-peak usage period.

Smart meters go a step further than simple AMR (automatic meter reading). They offer additional functionality including a real-time or near real-time reads, power outage notification, and power quality monitoring. They allow price setting agencies to introduce different prices for consumption based on the time of day and the season.

Another type of smart meter uses nonintrusive load monitoring to automatically determine the number and type of appliances in a residence, how much energy each uses and when. This meter is used by electric utilities to do surveys of energy use. It eliminates the need to put timers on all of the appliances in a house to determine how much energy each uses.

Prepayment meter and magnetic stripe tokens, from a rented accommodation in the UK. The button labelled A displays information and statistics such as current tariff and remaining credit. The button labelled B activates a small amount of emergency credit should the customer run out

The standard business model of electricity retailing involves the electricity company billing the customer for the amount of energy used in the previous month or quarter. In some countries, if the retailer believes that the customer may not pay the bill, a prepayment meter may be installed. This requires the customer to make advance payment before electricity can be used.relay.

In the UK, mechanical prepayment coin meters used to be common, both in private rented accommodation and residential customers of the Electricity Boards, the Nationalised Electricity sector. Disadvantages of these included the need for regular visits to remove the cash, and risk of theft of the cash in the meters by both customers and burglars.

The first automated pre-payment meters were introduced by London Electricity, in conjunction with the Slumberger Metering based in Felixstowe, UK. They were initially called Key Meters and later renamed Budget Meters. They avoided the 60,000 disconnections for non-payment per annum and the many disadvantages of cash prepayment. They were also popular with customers who wanted a convenient payment method, especially in short term tenancies. well over 1 million such meters were installed across the Uk in the first few years after introduction. Modern solid-state electricity meters, in conjunction with smart cards, have removed these disadvantages and such meters are commonly used for customers considered to be a poor credit risk. In the UK, customers can use organisations such as the Post Office Ltd or PayPoint network, where rechargeable tokens (Quantum cards for natural gas, or plastic "keys" for electricity) can be loaded with whatever money the customer has available.

In South Africa, Sudan and Northern Ireland prepaid meters are recharged by entering a unique, encoded twenty digit number using a keypad. This makes the tokens, essentially a slip of paper, very cheap to produce.

Around the world, experiments are going on, especially in developing countries, to test pre-payment systems. In some cases, prepayment meters have not been accepted by customers. There are various groups, such as the Standard Transfer Specification (STS) association, which promote common standards for prepayment metering systems across manufacturers. Prepaid meters using the STS standard are used in many countries.

Time of Day metering (TOD), also known as Time of Usage (TOU) or Seasonal Time of Day (SToD), metering involves dividing the day, month and year into tariff slots and with higher rates at peak load periods and low tariff rates at off-peak load periods. While this can be used to automatically control usage on the part of the customer (resulting in automatic load control), it is often simply the customer"s responsibility to control his own usage or pay accordingly (voluntary load control). This also allows the utilities to plan their transmission infrastructure appropriately. See also Demand-side Management (DSM).

TOD metering normally splits rates into an arrangement of multiple segments including on-peak, off-peak, mid-peak or shoulder, and critical peak. A typical arrangement is a peak occurring during the day (non-holiday days only), such as from 1 pm to 9 pm Monday through Friday during the summer and from 6:30 am to 12 noon and 5 pm to 9 pm during the winter. More complex arrangements include the use of critical peaks that occur during high demand periods. The times of peak demand/cost will vary in different markets around the world.

This exported energy may be accounted for in the simplest case by the meter running backwards during periods of net export, thus reducing the customer"s recorded energy usage by the amount exported. This in effect results in the customer being paid for his/her exports at the full retail price of electricity. Unless equipped with a ratchet or equivalent, a standard meter will accurately record power flow in each direction by simply running backwards when power is exported. Where allowed by law, utilities maintain a profitable margin between the price of energy delivered to the consumer and the rate credited for consumer-generated energy that flows back to the grid.

Lately, upload sources typically originate from renewable sources (e.g., wind turbines, photovoltaic cells), or gas or steam turbines, which are often found in cogeneration systems. Another potential upload source that has been proposed is plug-in hybrid car batteries (vehicle-to-grid power systems). This requires a "smart grid," which includes meters that measure electricity via communication networks that require remote control and give customers timing and pricing options. Vehicle-to-grid systems could be installed at workplace parking lots and garages and at park and rides and could help drivers charge their batteries at home at night when off-peak power prices are cheaper, and receive bill crediting for selling excess electricity back to the grid during high-demand hours.

Current transformers used as part of metering equipment for three-phase 400 A electricity supply. The fourth neutral wire does not require a current transformer because current cannot flow in the neutral without also flowing in metered phase wires. (Blondel"s theorem)

The location of an electricity meter varies with each installation. Possible locations include on a utility pole serving the property, in a street-side cabinet (meter box) or inside the premises adjacent to the consumer unit / distribution board. Electricity companies may prefer external locations as the meter can be read without gaining access to the premises but external meters may be more prone to vandalism.

Current transformers permit the meter to be located remotely from the current-carrying conductors. This is common in large installations. For example, a substation serving a single large customer may have metering equipment installed in a cabinet, without bringing heavy cables into the cabinet.

Since electrical standards vary in different regions, "customer drops" from the grid to the customer also vary depending on the standards and the type of installation. There are several common types of connections between a grid and a customer. Each type has a different metering equation. Blondel"s theorem states that for any system with N current-carrying conductors, that N-1 measuring elements are sufficient to measure electrical energy. This indicates that different metering is needed, for example, for a three-phase three-wire system than for a three-phase four-wire (with neutral) system.

In Europe, Asia, Africa and most other locations, single phase is common for residential and small commercial customers. Single phase distribution is less-expensive, because one set of transformers in a substation normally serve a large area with relatively high voltages (usually 230 V) and no local transformers. These have a simple metering equation: Watts = volts x amps, with volts measured from the neutral to the phase wire. In the United States, Canada, and parts of Central and South America similar customers are normally served by three-wire single phase. Three-wire single-phase requires local transformers, as few as one per ten residences, but provides lower, safer voltages at the socket (usually 120 V), and provides two voltages to customers: neutral to phase (usually 120 V), and phase to phase (usually 240 V). Additionally, three-wire customers normally have neutral wired to the zero side of the generator"s windings, which gives earthing that can be easily measured to be safe. These meters have a metering equation of Watts = 0.5 x volts x (amps of phase A − amps of phase B), with volts measured between the phase wires.

Industrial power is normally supplied as three phase power. There are two forms: three wire, or four wire with a system neutral. In "three wire" or "three wire delta," , there is no neutral but an earth ground is the safety ground. The three phases have voltage only relative to each other. This distribution method has one fewer wire, is less expensive, and is common in Asia, Africa, and many parts of Europe. In regions that mix residences and light industry, it is common for this to be the only distribution method. A meter for this type normally measures two of the windings relative to the third winding, and adds the watts. One disadvantage of this system is that if the safety earth fails, it is difficult to discover this by direct measurement, because no phase has a voltage relative to earth.

In North America, it is common for electricity meters to plug into a standardised socket outdoors, on the side of a building. This allows the meter to be replaced without disturbing the wires to the socket, or the occupant of the building. Some sockets may have a bypass while the meter is removed for service. The amount of electricity used without being recorded during this small time is considered insignificant when compared to the inconvenience which might be caused to the customer by cutting off the electricity supply. Most electronic meters in North America use a serial protocol, ANSI C12.18.

In many other countries the supply and load terminals are in the meter housing itself. Cables are connected directly to the meter. In some areas the meter is outside, often on a utility pole. In others, it is inside the building in a niche. If inside, it may share a data connection with other meters. If it exists, the shared connection is often a small plug near the post box. The connection is often EIA-485 or infrared with a serial protocol such as IEC 62056.

In 2014, networking to meters is rapidly changing. The most common schemes seem to combine an existing national standard for data (e.g. ANSI C12.19 or IEC 62056) operating via the internet protocol with a small circuit board for powerline communication, or a digital radio for a mobile phone network, or an ISM band.

Electricity meters are required to register the energy consumed within an acceptable degree of accuracy. Any significant error in the registered energy can represent a loss to the electricity supplier, or the consumer being over billed. The accuracy is generally laid down in statute for the location in which the meter is installed. Statutory provisions may also specify a procedure to be followed should the accuracy be disputed.

For the United Kingdom, any installed electricity meter is required to accurately record the consumed energy, but it is permitted to under-read by 3.5%, or over-read by 2.5%.

Meters can be manipulated to make them under-register, effectively allowing power use without paying for it. This theft or fraud can be dangerous as well as dishonest.

Power companies often install remote-reporting meters specifically to enable remote detection of tampering, and specifically to discover energy theft. The change to smart power meters is useful to stop energy theft.

When tampering is detected, the normal tactic, legal in most areas of the United States, is to switch the subscriber to a "tampering" tariff charged at the meter"s maximum designed current

A common method of tampering on mechanical disk meters is to attach magnets to the outside of the meter. Strong magnets saturate the magnetic fields in the meter so that the motor portion of a mechanical meter does not operate. Lower power magnets can add to the drag resistance of the internal disk resistance magnets. Magnets can also saturate current transformers or power-supply transformers in electronic meters, though countermeasures are common.

The owner of the meter normally secures the meter against tampering. Revenue meters" mechanisms and connections are sealed. Meters may also measure VAR-hours (the reflected load), neutral and DC currents (elevated by most electrical tampering), ambient magnetic fields, etc. Even simple mechanical meters can have mechanical flags that are dropped by magnetic tampering or large DC currents.

Newer computerised meters usually have counter-measures against tampering. AMR (Automated Meter Reading) meters often have sensors that can report opening of the meter cover, magnetic anomalies, extra clock setting, glued buttons, inverted installation, reversed or switched phases etc.

Some tampers bypass the meter, wholly or in part. Safe tampers of this type normally increase the neutral current at the meter. Most split-phase residential meters in the United States are unable to detect neutral currents. However, modern tamper-resistant meters can detect and bill it at standard rates.

Disconnecting a meter"s neutral connector is unsafe because shorts can then pass through people or equipment rather than a metallic ground to the generator or earth.

A phantom loop connection via an earth ground is often much higher resistance than the metallic neutral connector. Even if an earth ground is safe, metering at the substation can alert the operator to tampering. Substations, inter-ties, and transformers normally have a high-accuracy meter for the area served. Power companies normally investigate discrepancies between the total billed and the total generated, in order to find and fix power distribution problems. These investigations are an effective method to discover tampering.

Following the deregulation of electricity supply markets in many countries, the company responsible for an electricity meter may not be obvious. Depending on the arrangements in place, the meter may be the property of the meter Operator, electricity distributor, the retailer or for some large users of electricity the meter may belong to the customer.

The company responsible for reading the meter may not always be the company which owns it. Meter reading is now sometimes subcontracted and in some areas the same person may read gas, water and electricity meters at the same time.

The introduction of advanced meters in residential areas has produced additional privacy issues that may affect ordinary customers. These meters are often capable of recording energy usage every 15, 30 or 60 minutes. Some meters have one or two IR LEDs on the front: one used for testing and which acts as the equivalent of the timing mark on the older mechanical meters and the other as part of a two-way IR communications port for reading / programming the meter. These IR LEDs are visible with some night vision viewers and certain video cameras that are capable of sensing IR transmissions. These can be used for surveillance, revealing information about peoples" possessions and behaviour.Nonintrusive load monitoring gives even more detail about what appliances people have and their living and use patterns.

Ricks, G.W.D. (March 1896). "Electricity Supply Meters". Journal of the Institution of Electrical Engineers. 25 (120): 57–77. doi:10.1049/jiee-1.1896.0005. Student paper read on January 24, 1896 at the Students" Meeting.

Measuring Instruments (Active Electrical Energy Meters) regulations 2006, Schedule 1, Paragraph 15. These errors apply between +5°C to +30°C and a power factor of 0.8 leading to 0.5 lagging. Outside of these limits larger errors are permissible.

Teridian Semiconductors Application Note, "Antitamper Features Enabled by the 71M6511" The 71M6511 is a single chip metering device widely used in computerised meters.

Your water meter (usually located in the ground, at the front curb, or in the alley) measures the amount of water used in your household. Tucson Water takes the current reading and subtracts from it the previous reading to calculate your billing cycle water usage. Learning how to read your meter can help you verify the monthly reading on your water bill or determine if there is a leak on your property.

The water meter measures water use in cubic feet (one cubic foot equals 7.48 gallons). Tucson Water calculates water usage per every 100cf which is equal to 1 Ccf (748 gallon). To read your water meter, first look to see if the meter register has an analog (dial) or digital (LCD) display.

Analog displays use straight-reading dials which are read the same way you read your vehicle odometer. The last two digits on the meter dial are dropped when the meter is read. In the example at upper right, the meter reads 9 CCFs.

For the meter with the analog display, check the needle’s position on the meter dial and note the time. Check the needle’s position again after 15-30 minutes. If the needle’s position has changed, you may have a leak. Analog meters have low flow indicators represented by a white triangle or blue star located on the dial face, which turns with low flow making it easier to detect when water is moving through the meter. For meters with a digital display, check the gallons per minute flow rate display screen.  Any flow rate other than zero may indicate a possible leak. The low flow indicator is displayed on the right side of the screen, represented by a series of dashes rotating clock wise forming a zero.

If you identify flow in the meter there is a leak inside the house or between the water meter and the house, turn off your house valve. If the needle on the water meter dial (or the blue triangle) continues to move or the flow rate is anything other than zero, you may have a leak between your house and the water meter. If the needle has not moved or the flow rate is zero, you may have a leak within your house.