This high impedance circuit was found in 1967 documentation by Ferranti. The original operational amplifier is from that time. The circuit can be implemented with modern equivalents.
This effects circuit can be used with microphones or guitars. The circuit is from an American...
This circuit generates pulses whose frequency depends on C1. The circuit can be powered by...
I found this circuit in a 1998 publication, but as all components are common, it can be easily...