This resistance meter was found in an English documentation from 1989. The operational amplifier admits an equivalent and the transistor can be a BC558 or BC559.
In the figure we have the typical configuration of a sinusoidal audio oscillator with twin-T. The...
This circuit was found in a 1969 US documentation. It provides a signal that can be externally...
We found this adapter in a 1970s American documentation on instrumentation. It is suitable for analog...