Continue to Site

Welcome to our site!

Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

  • Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

0.1 uf electrolytic and 0.1 pf capacitors

Status
Not open for further replies.
You have absolutley no idea what you are talking about.
An FM station through one of my bugs sounds exactly like the radio station coming from the radio.
It does not and please stop arguing.
FM radios in your country have de-emphasis that cuts 3.2kHz to -3dB, 6.4khz to -6dB and 12.8kHz to -12dB. 15khz is reduced more.
The 22k collector resistor in the mic preamp transistor of your Wasp transmitter is bypassed with 1nF which cuts 7.3kHz another -3dB and steepens the high frequencies cutoff slope. It will sound very muffled on an FM radio.

My FM transmitter has pre-emphasis to cancel the de-emphasis in FM radios. My mic preamp transistor has a 10k collector resistor that is bypassed with 470pf so it cuts frequencies above 34khz so that 15kHz sounds good.

My FM transmitter has a low-dropout voltage regulator so its frequency doesn't change like yours does when the battery voltage is running down.
 
Would you care to post clip audioguru? A local FM station will do, preferably a song I know so I can download an appropriate clip for comparison =)
 
It's the expense of getting the extra components, such as the regulator, and even the enamelled wire, that put even the original poster off building it. That's why I supply kits for everything I produce.
Alkaline batteries are very expensive and not needed for 30mA circuits.

Out of more than 100,00 kits, no-one has commented on the fact that the transmitter does not clarity, and returned a kit.
I have compared the output from a radio and from a bug and could not tell the difference and I have a new $15 hearing aid from China, so I can hear it very clearly now.
 
Last edited:
It looks good to me strip board and all I would love to use strip board but haven't found any one that sells it in the US. And I never had any luck with solder less bread boards and fm transmitter. I all ways had to solder them up on a cheap board you get from radio shack. I don't think that board would look better if it was on a pcb. Very nice work.
 
I don't use a 7805 voltage regulator that has a dropout voltage of 2V. I use a low-dropout regulator that has a dropout voltage typically 0.05V or 0.2V max at the low current it is used for. Then my oscillator frequency is stable until the 9V battery voltage drops below 5.2V.

Doesn't an FM radio sound exactly the same as an AM radio with your hearing aid?
 
Alkaline batteries are very expensive? In what universe Colin? Colin, you constantly quote numbers in relation to units of the circuits you sell. But refuse to substantiate or post relevant performance information about them in any thread here. Can you prove all of those kits you sold resulted in someone transmitting a clear signal?
 
Would you care to post clip audioguru? A local FM station will do, preferably a song I know so I can download an appropriate clip for comparison =)
I don't need to post a clip. My FM transmitter has exactly the same pre-emphasis as FM radio stations have. It is the opposite to what all FM radios have. Nothing further cuts high audio frequencies so it sounds perfect to a person with good hearing.

Colin's FM transmitters produce a muffled sound.
 
Yes, and a clip from the both of you would shut the both of you up, as we would no longer be working in opinion although I would gladly include mine anyways, but simply show the spectrum involved in the clips captured and lay things to rest. The two of you can argue back and forth till the end of mankind as far as I'm concerned =)
 
I think you are right. The fact that you can hear a pin dop and the sound is exacly like you are in the room means the sound is severly muffled and distored.
I will start to organise to buy back all the 100,000 kits because they are definitely rubbish.
 
If you can produce a .wav file I can produce an FFT chart of the audio colin. I might be human, but FFT is data. It requires both of you participating though. How many 100 thousand kits have you sold cause so far I think you've said that at least a half dozen times.
Either you both post audio samples or you're both talking out your rear ends =)
 
Last edited:
The numbers say that Colin's is muffled and mine sounds perfect.
Try turning the treble tone control on your stereo all the way down. Colin's sounds worse.

All the good quality FM stereo transmitters made to broadcast your MP3 player to a car radio have pre-emphasis like my FM transmitter has. Colin's Wasp FM transmitter cuts the highs instead of boosting them.
 
Are you sure I can use any capacitor for that value? Shouldn't I use an electrolytic capacitor?

As for the 0.1 pf cap I will post the schematic so you can see. It is an ultra sensitive FM transmitter.

I thought that sounded a bit too small... but its on the schematic..

i'd call that a printing error (well human error) just use something a bit bigger should be too critical as its across the power supply so its got nothing to do with determining frequencies or anything
 
It looks good to me strip board and all I would love to use strip board but haven't found any one that sells it in the US. And I never had any luck with solder less bread boards and fm transmitter. I all ways had to solder them up on a cheap board you get from radio shack. I don't think that board would look better if it was on a pcb. Very nice work.


You mean The Source? WOW. I bought some PC board there and it was EXPENSIVE!!
 
I no I use a lot of there $1.99 boards like this one
 

Attachments

  • GEDC0299.JPG
    GEDC0299.JPG
    75.5 KB · Views: 214
I used genuine British epoxy-fiberglass Veroboard for about 15 years then it was not available in Canada anymore. The RadioShack one was very poor quality.
A local Chinese electronic parts store had an excellent copy of the epoxy-fiberglass Veroboard that I used for about 6 years.
The Chinese store stopped selling their stripboard but a nearby store had the Taiwan one I use now but it is cheap phenolic intead of epoxy-fiberglass.
 
But where can you get it online. I no the copper is easy to come off of them. But they work. just don't build your circuit wrong they don't like to be
re soldered
 
Last edited:
And audioguru Your fm transmitter Is very good design It should have very clear sound. Seeing it doesn't chop what most people hear. and coilns would be good for base like for this
 

Attachments

  • base.PNG
    base.PNG
    4.5 KB · Views: 147
Last edited:
I used genuine British epoxy-fiberglass Veroboard for about 15 years then it was not available in Canada anymore. The RadioShack one was very poor quality.
A local Chinese electronic parts store had an excellent copy of the epoxy-fiberglass Veroboard that I used for about 6 years.
The Chinese store stopped selling their stripboard but a nearby store had the Taiwan one I use now but it is cheap phenolic intead of epoxy-fiberglass.

hi agu,
Dont know if Farnell has a branch in Canada.:)

Your Search Results | Farnell United Kingdom
 

Attachments

  • 64073.pdf
    298.6 KB · Views: 162
Last edited:
And audioguru Your fm transmitter Is very good design It should have very clear sound. Seeing it doesn't chop what most people hear. and coilns would be good for base like for this
Colin's FM transmitters chop off high audio frequencies and chop off low audio frequencies.
My FM transmitter has cutoff frequencies of 21Hz and 20kHz.
 
Status
Not open for further replies.

Latest threads

New Articles From Microcontroller Tips

Back
Top