Almost anything that flows has to be controlled at some stage, from the flow of our rivers to the energy that keeps our buildings running. Take a simple electricity meter, we all have them in our homes and places of work. A single phase electricity meter designed for measuring electricity energy flowing in one or two directions in single phase 2 wire networks.

Electricity meters have a function called The Hall Sensor, based on the principle of the Hall effect, named after Edwin Herbert Hall an American physicist who discovered the "Hall Effect" in 1879. The magnitude of this discovery is extremely impressive considering how little was known about electricity in Hall's time and his discovery in still in use today. Examples are the ME200 and MT300 meters. They comply with IEC 1036 standard for class 2 0r 1 and manufactured in compliance with ISO 9001 standard. Supplied by Direct Metering Services.

Margaret Thatcher, the Prime Minister at the time launched an anti-crime initiative, part of it focussed on theft from coin operated meters. Far from today's technology, trials were carried out where plastic coins or tokens where crushed after insertion into the meter, thus rendering them useless. The benefits to the utility companies were that it was indeed true prepayment because cash was exchanged for tokens so they got their money before electricity was consumed, security could be managed easier and cheaper.

In the mid 1980's the first generation pre-paid electricity and gas meters were available. Two examples are; Magnetic card. These were purchased from outlets and encoded with the cash value. The flaws were such that they were not particularly secure. The Memory Key. An EEPROM (electrically erasable programmable read only memory ) encapsulated into a plastic key. More secure than the magnetic card and not all credit needed to be downloaded so funds could be saved for later. Also other data encoded on the key could trigger a change of rate or debt collected to enable payment of arrears.

Picture Courtesy of
Direct Metering Supplies Ltd