This circuit is from an 80's Radio Electronics. The circuit has several output options for 50 mA currents with load indicator through LEDs.
The transmitter shown can reach around 100 meters depending on the location and sensitivity of the...
This circuit converts a positive CMOS supply voltage to a negative one. We found it in a 90s...
The circuit shown in figure 5 generates square signals based on a transconductance operational amplifier...