Found in a 90s Popular Electronics, this circuit provides sinusoidal signals at frequencies given by the components, as shown in the table beside the circuit.
In the figure we have two simple configurations of voltage doublers. Resistors and diodes are...
This circuit was found in a former Popular Electronics. The timing is given by R1 and C1, R4 and...
This circuit that uses two LDRs as sensors was found in Radio Electronics magazine from November 1961....