With this circuit it is possible to use a frequency meter as a tachometer. The circuit was found in American documentation from the 90s. The phototransistor can be of any type.
This circuit generates an ultrasound whose frequency is set in P1. Reproduction is done on a...
This circuit was suggested by General Electric / RCA in a 1980s documentation. The components are of...
The circuits shown in figure 2 are suggested by Texas Instruments (www.ti.com) make use of the...