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.
Using the CMOS 4001 we found this circuit in the October 1974 Radio Electronics magazine. The...
This circuit for testing sources up to 10 A was found in the magazine Radio Electronics Special...
This bridge-biased transistor test circuit measures gain in the range 0 to 300. Circuit is from...