RPM / Tachometers Circuits
Available-light photo tachometer simplifies outdoor remote sensing: 01/25/99 Electronic Design - Ideas for Design / Tachometry, the measurement of the speed of rotating objects, is a common enough application that has many practical but few noteworthy solutions.
Digital Tachometer Avoids Analog Vices:11/10/94 EDN-Design Ideas / (requires a password)Optical Tachometer Provides Bidirectional Info: 05/21/98 EDN-Design Ideas / (requires a password)
Simple Circuit Measures Diesel's Rotations Per Minute: 03/04/99 EDN-Design Ideas / PDF contains multiple circuits - scroll to find this circuit. (have to obtain a password first) Tachometer Demodulator has Fast Response Time: 12/07/95 EDN-Design Ideas / (requires a password)Tachometer Measures Very Low Frequencies :08/23/04 Electronic Design - Design Briefs / The circuit shown in the figure is a three-digit tachometer that lets you measure low-frequency events recurring at intervals of 0.235 to 15 seconds--that is, from 4 to 255 rpm.