This circuit was found in old American documentation. Transistor is general purpose and coil rated is for 1.5 MHz. Wind 50 + 50 turns of wire 28 onto ferrite rod for 1 MHz.
This temperature compensated circuit was found in a 1980s American documentation. The power supply...
This circuit is an improved version of the previous ones with the LM3914. We found it in the March...
This indicator was found in a 1974 publication, but it can be fitted with the BC548 transistor or...