This 5 W transistor amplifier for the car was found in an English documentation from 1969. The transistors are from that time and the transformer is of a special type.
This circuit can use NTCs from 200 to 680 ohms, just change P2. For 200 ohms use 330 ohms, for 250...
This circuit was found in an Electronic Design from the 90's. It makes use of components from the...
This circuit for a frequency of 40 kHz was found in an old Electronic Design. There were no...