Hello.
I am trying to design an LC Colpitts oscillator.
This is the circuit. I came up with this based on the Colpitts oscillator shown on this website http://www.electronics-tutorials.ws/oscillator/colpitts.html, except that I did not have a high frequency-blocking choke to connect the collector to the positive power supply, and used the 10 K ohm resistor instead. The potentiometer biases the transistor.
What happens when I turn the circuit on is (1) It does not oscillate until I turn the power supply up to its maximum of 18 V. (2) The oscillation, at ~2 MHz, is very weak (millivolts). Why does the circuit require 18 V and how can I increase the signal amplitude? I tried connecting the collector to +V through the primary winding of a transformer (as a replacement for a choke) and got no oscillation. On another note, I tried using a the primary winding of a transformer as the inductor in the tank circuit, and that also didn't work...so if it's possible to make that work in some way, that would be helpful to because I have more transformers than I do inductors.
I am trying to design an LC Colpitts oscillator.
This is the circuit. I came up with this based on the Colpitts oscillator shown on this website http://www.electronics-tutorials.ws/oscillator/colpitts.html, except that I did not have a high frequency-blocking choke to connect the collector to the positive power supply, and used the 10 K ohm resistor instead. The potentiometer biases the transistor.
What happens when I turn the circuit on is (1) It does not oscillate until I turn the power supply up to its maximum of 18 V. (2) The oscillation, at ~2 MHz, is very weak (millivolts). Why does the circuit require 18 V and how can I increase the signal amplitude? I tried connecting the collector to +V through the primary winding of a transformer (as a replacement for a choke) and got no oscillation. On another note, I tried using a the primary winding of a transformer as the inductor in the tank circuit, and that also didn't work...so if it's possible to make that work in some way, that would be helpful to because I have more transformers than I do inductors.
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