This circuit detects changes in the active cycle of the input signal. The circuit was obtained in a 1966 EEE. Transistors are general purpose types of the time.
Suitable for battery powered microcontrolled applications this Texas Instruments circuit from its...
This amplifier with the LM1098 and LM101 by Motorola from a 1990 manual can be designed with more...
Found in a 1967 Ferranti documentation, this circuit uses a LDR from that time as a sensor....