Printed Resistors

1 1 Track length (m) 0.1 0.01 0.01 4 3 2 1mm EE June 1987 PRINTED RESISTORS by K Bachun Introducing an attractive alternative to hassling with lots of low value, high power, resistors in testing, designing and setting up power supplies, AF amplifiers, and the like. Have you ever worked on a cir- cuit whose operation depends largely on a power resistor with a value below some 0.5 Q? The experiments usually start with fitting a "near guess" power re- sistor from the junkbox, and end in disappointment at find- ing that the required value can only be realized with a tangled network of series and parallel connected resistors of sundry values and power ratings. Then, if the circuit finally works, the question arises how much re- sistance has actually been fit- ted. This is not at all easy to find out, since the common ohmmeter is not suitable for measuring below, say, 5 2, and the tolerance on every in- dividual resistor in the network makes it very hard, if not im- possible, to calcula...