This circuit was found in a 73 amateur radio magazine from the 90s. An LED extends the scale from 0 to 5 V to 10 to 15 V in this bargraph circuit. Other zener values can be used.
The circuit shown in the figure allows a pressure switch to be used to turn a load on and off in a...
The circuit shown in the figure modulates an infrared beam with a sinusoidal signal generated by a...
Found in a Popular Electronics from the 80's, this circuit triggers an SCR keeping an LED on when...