system for supplying pre-paid goods or services eg electricity to a user, comprising: a monitoring device locate at the user's premises for monitoring usage of goods or services, the device including a storage means for storing a signal indicative of the current amount of credit, a keyboard for entering an encoded ...

A power supply circuit for an electrical device is provided, the circuit comprising a resistor having conductive ends mounted on the surface of the circuit, and being of a predetermined value and weight such that application of an overcurrent to the circuit causes the resistor to become dismounted from the circuit u...

A split core current transformer, preferably of the clamp-on type compiising a core split into two sections, a secondary coil and a signal conditioning circuit, wherein the signal conditioning circuit is connected to the secondary coil so as to improve the performance of the current transformer by reducing the total...