We found this configuration in a 1974 publication. Transistors can be replaced with equivalents such as 2N2222. The circuit has a dynamic range of 60 dB.
This circuit is from 1968 documentation. We can assemble it with more modern components such as a...
Found in a 90s Silicon Chip documentation this circuit is intended to protect a speaker system in...
The UVTRON tube is an ultraviolet radiation sensor. In this circuit from Radio Electronics from...