This stereo circuit is from Japanese 1960 documentation. The circuit was originally designed to work with a tube amplifier, removing power from it. The transistors are germanium.
The scale of this scale uses LEDs, and its accuracy depends on the number of LEDs. We found this...
This circuit found in Hands On Electronics only connects a load, which in this case is an LED. The...
The sensor of this circuit is a common silicon diode and it directly drives a small cooler with a...