Negative Edge Differential Differential Amplifier LM3900 (CB4039E)

This circuit was found in the 1990 Motorola Linear Databook and can use almost any operational amplifier. The power supply must be symmetrical.

Analog Tachometer (CB1366E )
This circuit converts pulse frequency to current, which is indicated on an analog instrument. The...
Audio Relay (CB3968E)
This relay circuit with a dual channel MOSFET (not very common today) was found in an old American...
Signal Tracer with MW Radio (CB20509)
In the figure we have a simple signal tracer circuit to be coupled to the volume control of an AM...