Ing. Cristoforo Baldoni

This article deals with the Proteus simulation (version 7 and higher) of a low cost and very useful coils tester, easy to build by yourself. It ‘s the In-circuit LOPT (Line OutPut Transformer) Tester by Bob Parker that allows to evaluate the smooth functioning of a coil by turning on a number of different colored LEDs. It doesn ‘t measure the inductance value of a coil, but rather the ratio of its resistive part and the inductive part. This tester is very useful in finding coils with shorted turns, and wound components like yoke windings and SMPS transformers. Low loss components, will turn on four or more LEDs, while components with short circuits will turn on few or no LEDs. We ‘ll se how to implement and simulate with Proteus the circuit which consists of three sections: the low frequency pulse generator, the ring amplitude comparator and the LED bargraph display. We ‘ll se how to model a coil and try different values for the inductive and resistive component to validate the simulation. The Proteus simulation files of the device are available for download after accessing this article.