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rar0308
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A circuit is here.
I built this circuit. People say a frequency is determined only by tank circuit and C2 is nothing to do with the frequency.
But when i change C2 value, the output frequency changes.
for example when C2 is 6pF 150Mhz, 12pF 120Mhz 18pF 108 Mhz.
why is this happening?
i'm struggling to fit the frequencty to FM range i.e. 90-100Mhz
I used C1=30pF and inductor 1uH, i get 150Mhz
which is totally disagreeing with the formula i.e. a reciprocal of (2 pi Root LC) = 29Mhz.
when i used 0.1uH it was still 150Mhz. It seems the output frequency is not solely determined by the tank circuit.
and I'm using low q factor variable capacitor. is this affecting this also?
edit : what is the official name of this circuit? I want to know the name to find information about this. people say it's not Hartley nor Colpitts.
24pf 98Mhz 30pF 92Mhz. Vpp is 500mV in Oscilloscope.
I connected 1000uF i.e. 10^9pF parallel to L. The frequency dropped from 105Mhz to 82Mhz.
A thing I built on PCB.
also i used different transistor KSP2222A instead of 2N2222
I built this circuit. People say a frequency is determined only by tank circuit and C2 is nothing to do with the frequency.
But when i change C2 value, the output frequency changes.
for example when C2 is 6pF 150Mhz, 12pF 120Mhz 18pF 108 Mhz.
why is this happening?
i'm struggling to fit the frequencty to FM range i.e. 90-100Mhz
I used C1=30pF and inductor 1uH, i get 150Mhz
which is totally disagreeing with the formula i.e. a reciprocal of (2 pi Root LC) = 29Mhz.
when i used 0.1uH it was still 150Mhz. It seems the output frequency is not solely determined by the tank circuit.
and I'm using low q factor variable capacitor. is this affecting this also?
edit : what is the official name of this circuit? I want to know the name to find information about this. people say it's not Hartley nor Colpitts.
24pf 98Mhz 30pF 92Mhz. Vpp is 500mV in Oscilloscope.
I connected 1000uF i.e. 10^9pF parallel to L. The frequency dropped from 105Mhz to 82Mhz.
A thing I built on PCB.
also i used different transistor KSP2222A instead of 2N2222
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