This circuit provides an audible signal when testing a TTL circuit. The circuit is from an old documentation, being fed with the 5V of the circuit under test.
This circuit, from Texas Instruments documentation, fires a relay when light strikes the...
This circuit was found in documentation from the 1980s. The circuit can be implemented with other...
This circuit is from an 1977 American publication. The coil consists of 30 + 70 turns of 28 AWG...