This automotive circuit was obtained from an 80's schematic from the integrated circuit factory itself. The voltage regulator is still common, but the operational amplifier is of the time.
This oscillator uses a general-purpose transistor that can have BC548, BF494 or 2N2222 equivalents and...
Offset Adjustment on an Amplifier with the LM139 (CB14245E) In the figure we have the way of...
The critical components of this 1978 circuit are transformers, which, hopefully, can be obtained from...