This circuit is from the Motorola LinearDatabook of 1990. It shows how it uses the LF355, 356 and 357 operational capacitive loads. The power supply must be dual.
When the supply is established, the load only receives the supply some seconds later, a time that...
With S1 closed, when dark, the triac will supply the load with the power set in R4. The LDR is...
This interesting amplifier for frame antenna for the medium wave range was found in a Popular...