Colpitts Common Base BJT Oscillator

Shake to start. This circuit is the common-base variant of the Colpitts oscillator, I've had a hard time finding any theory on its operation so I may be wrong, the inductor and capacitors in the collector tank are the standard Colpitts design, the feedback is capacitively coupled to the emitter, once the emitter voltage is greater than the base voltage (about 5V in this case) current charges the base capacitor above the supply voltage which then forward biases the base-collector junction, the charge on the capacitor discharges through the tank maintaining oscillation. I've not built this yet however it's a fairly standard design, please comment if you have anything to add.

published 10 years ago