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Hi guys,
Let me update, I built it on a propotype board:
The output signal to spectrum analyser is pin C of Transistor Q3. I added the bypass/filter capacitor already.
I tried to measure the L by a LC200 LC meter (not a very good one but fairly ok, I tested it with some standard L and C)
It...
Thanks betwixt,
I did add the capacitor as your suggestion, it strengthens the output signal and increase the 1st frequency, but still at around 45MHz. I'm trying different coil setup to see how the output will be.
I tried to measure the L directly, it's confirmed that L value is more than double what I calculated by inductor tool. So the frequency calculation is correct.
I tried some of other calculation website, it shows correctly with the tool...
My frequency calculation is quite straightforward, using Colpitts oscilator:
The inductor calculation:
So we have
L= 251.97 nH
C1= 22p
C2= 47p
==> f= 82 Mhz
I will follow the advise to directly measure the L value.
thanks for your support.
Hi everyone,
I'm building a small FM transmitter circuit as following. It works fine and I can listen the sound from microphone by a FM radio.
This transmitter is design at around 82 Mhz ( L is 0.5cm diameter, 8 turns of 0.5mm wire). The Colpitts frequency calculation confirmed this...
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