Found in a Hands-On Electronics from the 90s, this circuit produces the dial tones of an old telephone. The integrated circuit used is uncommon today.
The purpose of this circuit is to monitor the output voltage of a power supply. The under and over...
Old multimeters used a 22.5 V battery for high resistance measurements. If you have one, you...
In the figure we show a monostable that uses two of the four ports available on 4001. The duration of...