Hello, can somebody help wich transistor is like bfg520

[Audioguru]

0.1μF feeding 500k ohms has a cutoff frequency (-3dB) calculated to be extremely low at 3.2Hz. We cannot hear below 20Hz and many speakers cannot produce frequencies below 35Hz.

I do not know the inductance values you have. 470pF might not be a good value for them.
Look in Google for an LC Resonance Calculator.

I cannot understand your broken English. Is there a forum in your country in your own language?

 

[michael1978]

0.1μF feeding 500k ohms has a cutoff frequency (-3dB) calculated to be extremely low at 3.2Hz. We cannot hear below 20Hz and many speakers cannot produce frequencies below 35Hz.

I do not know the inductance values you have. 470pF might not be a good value for them.
Look in Google for an LC Resonance Calculator.

I cannot understand your broken English. Is there a forum in your country in your own language?

One simple question
Do you understand this circuits(i think yes, you know)
So you said it resonate at 5.1mhz, wich one are those LC circuits in schematics?(wich make lc at 5.1Mhz) wich capacitor and inductance, can you look in circuits and you can tell me, and problem is solved i think those are better forum

 

[Audioguru]

I did not say anything resonates at 5.1MHz. I said your signal generator in the simulation wrongly produces 5.1MHz instead of the correct 10.7MHz. Your schematic has more errors.

The black and white schematic I posted is correct and widely used. It clearly shows the tuning capacitors parallel with the transformer coils.

 

[michael1978]

I did not say anything resonates at 5.1MHz. I said your signal generator in the simulation wrongly produces 5.1MHz instead of the correct 10.7MHz. Your schematic has more errors.

The black and white schematic I posted is correct and widely used. It clearly shows the tuning capacitors parallel with the transformer coils.

yes that right, i correct it but it has no correct wave,

about the second circuit is so design for 5.1Mhz, not for 10.7 MHZ, but i draw it in ltspice i thought he gonna explain how to change in the book , but i did not explain

 

[michael1978]

yes that right, i correct it but it has no correct wave,

about the second circuit is so design for 5.1Mhz, not for 10.7 MHZ, but i draw it in ltspice i thought he gonna explain how to change in the book , but i did not explain

But did you run it, the file is working perfect

 

[michael1978]

But did you run it, the file is working perfect

I go to change, but one more time i with no ask you anymore, is rely this circuit wrong, you know man i dont understand how he can do such big mistake

 

[(*steve*)]

@michael1978, arguing with yourself is a bad sign.

 

[michael1978]

I go to change, but one more time i with no ask you anymore, is rely this circuit wrong, you know man i dont understand how he can do such big mistake

I change the audioguru, but i did not know wich value to put in R and C, can you told me please

 

[michael1978]

@michael1978, arguing with yourself is a bad sign.

I dont know Steve, to make mistake in book...

 

[michael1978]

I go to change, but one more time i with no ask you anymore, is rely this circuit wrong, you know man i dont understand how he can do such big mistake

I did not say anything resonates at 5.1MHz. I said your signal generator in the simulation wrongly produces 5.1MHz instead of the correct 10.7MHz. Your schematic has more errors.

The black and white schematic I posted is correct and widely used. It clearly shows the tuning capacitors parallel with the transformer coils.

HI, Audioguru, can you please help for values of RC, for tank circuit i gona take it to make, i have this site and here is for lc formula etc....http://www.zen22142.zen.co.uk/Theory/tunedcct.htm please

 

[Audioguru]

Will you buy 10.7MHz transformers and a discriminator? They were sold 40 years ago but not today. Today an FM radio uses crystal filters instead of transformers. Digikey has 10.7MHz IF bandpass crystal filters and crystal filter discriminators.

 

[michael1978]

Will you buy 10.7MHz transformers and a discriminator? They were sold 40 years ago but not today. Today an FM radio uses crystal filters instead of transformers. Digikey has 10.7MHz IF bandpass crystal filters and crystal filter discriminators.

Hi, Audioguro please try to understand me , my intention is to make a fm tuner from ZERO and i get enough help from you and other peopels, and when i finish (after is easy i buy complete chip radio,), because after i know how is working, that is, ( and i rad also from here, they dont show the value of components for detector http://www.rfcafe.com/references/electrical/NEETS-Modules/NEETS-Module-12-3-11-3-20.htm) please try to understand me, you have just to tell wich value for rc and after i think i almost ready to complete all parts, thnx

 

[Audioguru]

Today, where will you buy 10.7MHz IF transformers and a 10.7MHz discriminator transformer or a 10.7MHz ratio detector transformer? They might have the tuning capacitor inside. Crystal filters replaced IF transformers years ago.

You want to know the values of WHICH rc? You posted a txt file where I cannot see the schematic. Please post the schematic (a print screen).

 

[michael1978]

Today, where will you buy 10.7MHz IF transformers and a 10.7MHz discriminator transformer or a 10.7MHz ratio detector transformer? They might have the tuning capacitor inside. Crystal filters replaced IF transformers years ago.

You want to know the values of WHICH rc? You posted a txt file where I cannot see the schematic. Please post the schematic (a print screen).

Ok Here, the value of R4, R5, and C3, C4, please

 

[Audioguru]

I am glad to see that you turned around the diodes so that are not conducting all the time.
Now you have the anodes of the diodes not connected to the transformer.
Also you have coil L4 and C10 shorted to the positive supply with C5.
The schematic does not have a positive supply so it will not work and will not simulate.

 

[michael1978]

I am glad to see that you turned around the diodes so that are not conducting all the time.
Now you have the anodes of the diodes not connected to the transformer.
Also you have coil L4 and C10 shorted to the positive supply with C5.
The schematic does not have a positive supply so it will not work and will not simulate.

You right look what i have forget most importing things, i i go to change thanks but what about values?

 

[michael1978]

You right look what i have forget most importing things, i i go to change thanks but what about values?

I am glad to see that you turned around the diodes so that are not conducting all the time.
Now you have the anodes of the diodes not connected to the transformer.
Also you have coil L4 and C10 shorted to the positive supply with C5.
The schematic does not have a positive supply so it will not work and will not simulate.

I dont know is good working, what do you think, again i have probem with frequency,

 

[Audioguru]

You made your schematic with the parts too far apart then the text is too small to see.
Also you did not right click on the schematic part of the simulation then select "View" then select "Zoom to Fit".
The large sinewave that is slowly reducing its level is 667kHz. Why?
You still have some mistakes I showed before. Why?

 

[michael1978]

You made your schematic with the parts too far apart then the text is too small to see.
Also you did not right click on the schematic part of the simulation then select "View" then select "Zoom to Fit".
The large sinewave that is slowly reducing its level is 667kHz. Why?
You still have some mistakes I showed before. Why?

I Realy dont know, where to connected, this i change diode
look now

 

[Audioguru]

Michael, you do not know what you are doing. I am ready to quit trying to help you.