We found this circuit in the 1957 Raytheon transistor application manual. The transistor can be a BC558 and the common 6 V relay, just by using this voltage in the supply.
The purpose of this circuit is to provide a few watts of power to a heavy speaker with good sound...
This circuit, found in US documentation, can measure the power of transmitters up to 10 W, given...
This circuit was obtained in a 1975 documentation. It is intended for old vehicles that still use...