This circuit allows the activation of a remote telephone bell made with a common piezoelectric capsule. The circuit does not need power, as it is powered by the line call signal itself.
This digital / analog converter shield is suggested by MOTOROLA and is based on an operational amplifier...
This circuit is from old documentation and can be assembled with 2N2646 for the unijunction and...
This three-transistor amplifier uses a JFET at the input to increase the input impedance. The...