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 A3906 integrated circuit from Allegro Microsystems (www.allegromicro.com) consists of a PWM...
This analog TV circuit can be used on a small transmitter. The circuit is from an 80's American...
This circuit is from an Electronics Now from the 90s. It applies to almost any operational...