Hi
I've been asked to design a Colpitts oscillator for a digital grid dip meter. I do have some requirements according to frequency range and specific components. To change the frequency of the Colpitts oscillator an old air variable capacitor should be used, more specific it's a capacitor ranging from 50 pF to 500 pF. Another important detail is that the coil is meant to be changed in order to cover the frequency range. The frequency range must be at least from 35 kHz to 1 MHz.
I've have been trying for a while, but can't figure out, what I'm gonna do. I've tried designing a circuit with a JFET amplifier voltage-divider biased, but everytime I change the value of coil/inductor it all goes wrong. Is there another and better way to do it, or what am I missing/doing wrong? Appreciate any help
I've been asked to design a Colpitts oscillator for a digital grid dip meter. I do have some requirements according to frequency range and specific components. To change the frequency of the Colpitts oscillator an old air variable capacitor should be used, more specific it's a capacitor ranging from 50 pF to 500 pF. Another important detail is that the coil is meant to be changed in order to cover the frequency range. The frequency range must be at least from 35 kHz to 1 MHz.
I've have been trying for a while, but can't figure out, what I'm gonna do. I've tried designing a circuit with a JFET amplifier voltage-divider biased, but everytime I change the value of coil/inductor it all goes wrong. Is there another and better way to do it, or what am I missing/doing wrong? Appreciate any help
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