This balance or balance circuit with phase inversion was found in documentation from the 90s. Transistors can be low noise equivalents like BC549.
This low frequency square wave oscillator using the 741 Operational Amplifier produces sound when...
This code practice oscillator was found in an English publication from the 80's. The circuit can...
This well-known configuration was found in a 1982 publication. Other operational amplifiers can be...