This configuration is from the 70s, having been found in an American documentation. The transistors can be BC549 for Q1 and BC548 for Q2.
The circuit presented is suggested by National Semiconductor in its Linear Applications Handbook. The...
In this application we show how to get tuning from 0 V to an LM350 regulator IC. The setting also...
This frequency corresponds to musical note C3. Frequency accuracy depends on the accuracy of the...