We found this circuit in a publication from the 1980s. Transistors can be replaced by current equivalents. The circuit is for 6 V and the capacitors determine the frequency of the oscillations.
We found this active crossover in a Radio Electronics magazine from June 1961. Note the different...
Found in Popular Electronics from the 90s, this circuit serves to indicate the output level of a...
If you are on an old PC that you use for experiments, control or other applications, this circuit is...