We present the circuit of the commercial transistor tester Sanwa SC2 sold in Japan in the 1960s. The circuit has several scales and types of test being powered by a 22.5 V battery.
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...