We found this circuit in a technical documentation for the National Semiconductor LM3909. The circuit consists of a low consumption continuity tester powered by a single battery.
This circuit for incandescent light bulbs was suggested by General Electric in a 1980s...
This circuit acts as a VU-meter when connected at the output of any audio amplifier, triggering a...
The circuit shown in figure 3 uses a programmable unijunction transistor (PUT) of the BRY39 type...