A Multipurpose Transistorized Tachometer

Abstract

The paper describes the development of a transistorized tachometer intended for manifold applications like speed measurement, speed control, recording speed-time characteristics, indicating any preset speed of a rotating body. Rotational speeds are translated into periodic electric pulse signals with the help of a small toothed magnetic disc mounted on the rotating shaft and a permanent magnet pick up fixed in space adjacent to the disc. An electronic integrator converts the frequency of the pick up signal to a directly proportional d.c. voltage, which becomes a measure of speed. The tachometer using all silicon transistors possess an accuracy better than 1 per cent over a speed range of 0–25000 r.p.m. and exhibits a very good thermal stability up to 60°C.