With this circuit it is possible to vary the resistance by adjusting the mark/space reaction of the 555. The circuit was found in the November 1989 Radio Electronics magazine.
This 80's circuit uses an integrated amplifier of the era, but nothing prevents it from being...
This circuit produces horizontal lines or bars in a analog TV tuned between channels 2 and 5. L1...
This circuit can be used to add a delay to a logic signal as shown by the input and output...