Sir tomorow i gonna send you; i go now to sleep, thanks for time, have a nice sleep
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Hello, can somebody help wich transistor is like bfg520
- Thread starter michael1978
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Yes you are right, i gonna make now your oscillator, but one thing is possible to explain, when i dont connect the varicap, the sinewave is everything ok, but when i connect i get harmonis of bad sinewave, whait i will show you now my circuits...
I make the circuits which he show me the, but i cannot change the frequency
Hello sir, i make the circuits, but i cannot change the frequency?
YES SORYY,I TRY, BUT I TRY TO OUTPUT OF TRANSISTOR 2, why i does not change in transistor 2 output
Hi again. I am pleased to see that you have now copied my schematic and that you are getting your simulation to work.
I have no problem changing frequency.
By varying my V3 or your V1 from 10Vdc to 1V dc, I get a change in frequency from 107.49MHz (at 10V) to 99.28MHz (at 1V).
If the varactor diode is connected backwards then it is not a variable capacitance part any more. Here is how it should be connected.
I am glad to hear that you built the circuit instead of simulating it because maybe your sim program does not know that a varactor diode changes its capacitance when you change the DC voltage across it.
If you built the circuit on a solderless breadboard then it will not work because capacitance between all the strips of contacts and wires is much too high. What meter did you use to measure its frequency?
I am glad to hear that you built the circuit instead of simulating it because maybe your sim program does not know that a varactor diode changes its capacitance when you change the DC voltage across it.
If you built the circuit on a solderless breadboard then it will not work because capacitance between all the strips of contacts and wires is much too high. What meter did you use to measure its frequency?
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The "Sim" knows all it needs to about the Varactor diode. My version works fine. I think our protagonist is still trying to simulate, it's just that his terminology is a bit misleading / confusing.
I agree with you comments about building on strip board. It can be made to work (I made versions back in the early 70's which worked OK) by stripping of all the unused tracks so that you are just left with the bits that have been used for the interconnects. Then give it a good clean to remove all the cr*p.
Hello Audioguro, my circuits old is working perfect, only i remove the filters(THAT WAS THE PROBLEM)
Hello sir, i build your circuit is working perfect, but also mine old circuits is working perfect, the problem was only filtes, so i just remove all filters and now perfect is working....
One more time me, why you use that 8ohm resistor in serie with inductor?
Hello sir i think i ask you of i forget, the what DO the resistor 100m, why he dont work from 88 to 108mhz, how can i build, because like i said my circuits he dont work i want to use yours like said maybe the mak mistake, i understand you now
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AS I explained somewhat earlier, the 100mΩ resistor in series with L1 is actually the dc resistance of the coil and is not an additional resistor. R4 is there purely for the simulator otherwise it thinks that L1 is a perfect inductor. This means that L! will then have an impossibly high Q which will affect results.
Why have you resorted to the old circuit with C10 in series with L1 along with all the errors of your original circuit which clearly does not work?
Also, if you tried to simulate the circuit in post #95, it won't work for apart from the basic errors, you have a transistor that is not connected to anything and one end of C6 left dangling. The spice platform does not like components being left like that and will simply refuse to work even if, the rest of the circuit is correct (which it isn't).
Thnx for explain, but i make the circuits like yours in -#71
look this one i make mistake i forget to connect 47P in serie with varicap, i dont know what mistake i make now?
Is orginal you circuits, you think software problem?
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