Using transistors at the time, this circuit was found in a 1970s documentation. Transistors support modern equivalents for 2A currents at least in the case of the output transistors.
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...