This circuit generates signals for adjustments in FIs of 10.7 MHz. The transistors can be BC548 or equivalent. We found this configuration in a documentation from the 70s.
Found in a Maxim documentation, this 1980s circuit drives 4 LEDs on a bar scale. The circuit does...
The circuit with a common operational amplifier uses a zener as a reference. The circuit is from...
We found this circuit in an English documentation from 1995. The frequency is given by the...