It is an improved version of the previous circuit with a voltage follower that reduces the load impedance. The circuit was found in American documentation from the 1980s.
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...