This dual balanced modulator configuration was obtained in a 1980s telecommunications documentation. The circuit makes use of transformers and the diodes are commonly used.
The frequency of this astable depends on the capacitor that can be changed over a wide range of...
This circuit is from a documentation from the 90s. The transistor can be any general-purpose FET...
In the figure we have one of the many options found in this section for an intercom using ordinary...