We found this active crossover in a Radio Electronics magazine from June 1961. Note the different adjustment ranges. The signal must be applied to the amplifier input.
The operational amplifier can be of any type in this circuit, found in a 1974 publication. The...
Found in a 1967 General Electric SCR manual, this circuit triggers in case of excess current,...
With this configuration it is possible to obtain an 80 dB gain from two 741 operational...