I built a 36Khz LC parallel tuned circuit driven by a transistor biased at
2mA. It was for use in detecting IR signals from IR remote controls. It works well enough with a measured bandwidth of about 4Khz at the -3dB points which would be a Q of about 9. As I remember, the unloaded Q of a parallel LC circuit is XL / R. The LC values are 2700pF and 6.8 mH with about 60 ohms of resistance in the inductor wire which equates to about 1500 / 60 =- which is more than twice the measured Q. I found a Q calculator at formatting linkwhich indicates .the loaded Q is 9 if the generator impedance is about 22K. So, my circuit must have an impedance of
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