This circuit is from an American documentation from the 90s. The transistors are of power and must be equipped with good heat sinks as well as the integrated voltage regulator.
In the figure we have the basic configuration of an operational amplifier for audio signals. The...
This General Electric circuit produces pulses of light only when light stops shining on the...
Found in an Electronic Design of 1964 this circuit has a control for the frequency and another for the...