High gain radio (CB21922E)

This simple 1 transistor radio was found in Raytheon's transistor manual. The transistor is germanium from the 60s.

VLF Converter (CB26333E)
With this circuit, signals in the range of 10 kHz to 150 kHz can be received at close to 4 MHz...
Variable Threshold Limiter (CB19490E)
This limiting circuit with an operational amplifier has an adjustable cut-off point and can use...
Photo trigger (CB8281E)
Published by Philips in 1965 documentation, the sensor for this circuit is a common LDR. The...