This circuit identifies the polarity of DC signals and if the signal is AC. The circuit is from 1969 US EDN documentation. Operational may be equivalent.
This circuit from an old documentation includes the power supply for the 117 V power grid. It can be...
The frequency of this circuit is approximately 1 Hz. Whenever the output is at low level, the LED...
This circuit has been found in an old documentation and therefore uses a lamp as an indicator. In a...