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.
We found this circuit in an American 80's documentation. The resistors must be of high precision...
The circuit shown is a Pierce type oscillator and operates at the fundamental frequency of the...
In the circuit shown in the figure we have the way to excite a small speaker from a TTL output. The...