Found in American documentation from the 1980s, this circuit has a diode feedback. At the exit we have an indicator LED. The LM3900 is a transconductance operational amplifier.
This circuit was found in an Analog Devices publication from the 1990s. The circuit performs input...
Found in Motorola documentation from the 90s, this circuit can be implemented with current...
We found this circuit in an old documentation for hams. In it we have the way to use a varicap to...