Colpitts Oscillator

My first attempt at creating my own air-core inductors.
2 different air-cores
My cores aren't 150nH... haven't calculated them yet,.
Shorter coil produces this waveform. Bottom waveform is at ALT MAG (x10)
Longer coil produced this
Scope output fed to counter. Smaller coil generates approx 29MHz- 0.03uS
Larger coil generates approx. 24MHz - 0.14uS
Close up of waveforms.
Smaller coil is 2 turns around 10mm dia former. calculated as 590nH
Larger coil is 12 turns around M6 bolt thread. calculated as 890nH.

1 comment:

  1. great circuit... if u ever assemble a VHF oscillator.. the loss is 80.5% or freq × 19.5% or value on capacitors in the tank in of multiplied by 19.5% and value of coil multiplied by 0.195 for true value of resonant components in breadboard

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