QUICK_DISCONNECT_TACHOMETER

Published:2009/7/16 3:37:00 Author:Jessie | From:SeekIC

Can be connected and disconnected from engine fast enough for production-line speed adjustments. Pulse is picked up by curved probe that is hooked over ignition cable in use. Probe is made from RG58A/U coax with 1 inch of shield removed to provide coupling. Resulting pulse picked up is about 1 v, with width of about 20 microsec. Pulse is fed lo first stage Q1 of monostable mvbr, which acts on Q2 to give pulse with constant height and width, having engine spark frequency. Meter gets current pulse through emitter-follower for each spark, so average meter current is proportional to rpm.-Transistorized Tachometer, Electronic Circuit Design Handbook, Mactier Pub. Corp., N.Y., p 154.



Reprinted Url Of This Article:
http://www.seekic.com/circuit_diagram/Automotive_Circuit/QUICK_DISCONNECT_TACHOMETER.html

Print this Page | Comments | Reading(3)