This circuit triggers an LED when the input signal exceeds the peak, or the value set in RV1. The transistors can be the modern equivalents BC549.
This 3-transistor circuit is from a 1963 publication. The transistors are from the time, but the...
This circuit incorporates the passive control of the previous circuit and was also found in the...
This voltage regulator was obtained in the SGS manual of linear integrated circuits of 1982. The...