This 4-transistor amplifier can work from 4.5 or 6 V power supplies. We found it in a Mullard transistors manual from 1960. The transistors are from the time.
This circuit generates signals from 50kHz to 10MHz, depending on the crystal used. The transistors can be...
The transistors in this circuit from a 1994 technical publication may be BC548 and the 12 V supply...
In the figure we have a simple logic level indicator for TTL circuits or powered by 5 V....