Found in a Radio Electronics store from the 90s, this circuit is for cars of that era. The circuit uses a 2N3055 that must be equipped with a heat sink.
For times in the range of seconds to a few minutes we found this timer with the CK722 in a Radio...
We can use this amplifier with low impedance headphones with good performance. Possible...
Found in a 1964 Electronic Design, this circuit uses transistors from that time. Equivalent...