This amplifier step for small signals can use any general-purpose transistor like the BC548. The circuit can be powered by voltages from 6 to 12 V.
The coil can be formed by 100 turns of 26 or 28 wire on a ferrite rod in this medium wave radio...
This circuit is from a 1968 Electronic Design. The characteristics of the output transformer are not...
This circuit is from a 1970 publication, having been implemented with germanium PNP transistors. We can...