LED current sensor - simple, but effective

/ simple, but effective It is sometimes necessary, or at least desirable, to be able to detect relatively large a.c. currents. One way of doing this is to use a LED in a network with resistors and/or 1N4001 diodes. This is, however, not such a good idea as there will always be a certain amount of voltage "lost", across the LED if nowhere else. From a technical point of view there are better ways of detecting the cur- rent, such as using current trans- 220V formers. The advantages of this method are that the current to be measured can be converted to a value that better suits the measuring equipment and the transformer pro- vides a distinct separation between the value that is measured and the measuring equipment. This latter point is particularly important as the measured value is often extremely high. Moving on to the practical side of things; we have been talking about a current transformer but what we ac- tually used is a normal mains transformer. The low-voltage winding is con...