This circuit mimics the trill of a bird. We found it in an American documentation from the 90s. It is based on the LM3909 integrated circuits.
This circuit is from old documentation. Based on two operational amplifiers of the time, it can be...
This Wien bridge oscillator was found in Radio Electronics from the 90s. The circuit uses the 741...
This circuit is from Mallory 1968 documentation. The circuit makes use of period components and...