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.
In fact, this 1967 Electronic Design circuit generates two symmetrical ramps whose frequency...
This basic configuration of an astable multivibrator was found in a publication of the year 1968....
This automotive tachometer circuit uses a FET and a 1 mA full-scale instrument. We found it in the...