This circuit was found in a 90’s 303 Circuits. The components are from the period and the heating system depends on the resistive element.
This high impedance and low capacitance buffer employs a junction FET that can be BF245 or...
We found this circuit in a 1976 publication for radio amateurs. It was originally intended for use in...
This circuit was found in a 90s American documentation. The circuit uses an LED that can be of a...