Easy AM Transmitter!

Picture of Easy AM Transmitter!
You are going to build an AM radio transmitter AND you will be shown how it works. When you finish your radio, it will look something like mine in the picture above.

I have attached the PDF file in the last step to this Inst'able for those without a pro membership.
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Step 1: Parts and Prep (Small Stuff)

Picture of Parts and Prep (Small Stuff)

==These are the small components you will need==

--Small Stuff--
- 555 timer chip
- NPN transistor
- two #103 capacitors (0.01 microfarads or 10,000 picofarads)
- #102 capacitor (0.001 microfarads or 1,000 picofarads)
- some short wires
- two 1 Kilohm resistors
- 10 Kilohm resistor
- 1/8 inch (3.5 millimeter) female audio jack (yours may have more or less than three
    wires, but it must have at least two)
- 5 Kilohm potentiometer 

==see next step for bigger components==

Step 2: Parts and Prep (Bigger Stuff)

==These are the bigger components you will need==

--Bigger Stuff--

- 1/8 inch (3.5 millimeter) male audio cable
- AM radio receiver
- Antenna. Yours doesn't have to be made out of a pop can, but the pop can works
- Breadboard

(see previous step for the small components)

Step 3: Schematic!!

Picture of Schematic!!

                  ==Now that we have all of our components ready, lets put this together!==

                                    I suggest constructing this on a breadboard first.
                          If you don't have a breadboard, you are definitely missing out!
                                                If you have any questions... ASK!

                                                P.S. Don't forget to SUBSCRIBE!       : )
karlitoboi21 days ago

sir...good day! i would like to ask a question...

a simple question...

what is the typical range of the radio receiver from the transmitter?

im talking about its radius... just to clarify...tnx sir.

JigMcFigg2 months ago

I was wandering what formula you used to calculate the frequency range, or did you just plug parts in and see what range was there?

jensenr30 (author)  JigMcFigg2 months ago

good question! I used this online utility to calculate the frequency using different component values.

raven_squire3 months ago

How would you get a range between 27 Mhz and 49 Mhz ?

jensenr30 (author)  raven_squire3 months ago

Well, if you wanted a frequency somewhere in that range, chances are you would not want a 555 timer. I don't think they work that fast. You might want to look into transistor RCL oscillators like the colpitts oscillator and other similar ones.

Hope that helps!

sir when i tuch my hand with potentio meter then i heard audio
with out tuching transmiter does not work clearly................ why
and when i eject NPN and antenna from circut transmiter waking still
pleas helf me
Rajyedke4 months ago
what is voltage of power supply used here ? ?? where to connect it???
Rajyedke4 months ago
what is the voltage of power supply here..??? where to connect it ..??? sry i couldn't understand??
imaduddin6 months ago
thx guys, it's work but the sound is little loud, any suggestion?
jensenr30 (author)  imaduddin6 months ago
use a resistor in series with your speaker or turn down the volume on your radio.
bilsat6 months ago
Hello, i cant find the needed stuff for the transmitter.i dont know where to find them in my country, greece and i do not want online purchases of any form.
looney1236 months ago
Hi. this may sound stupid but isn't this an AM transmitter ? So we should put a Mic in the audio jack not an earphones right ?
jensenr30 (author)  looney1236 months ago
in general it would be used to transmit any kind of signal. I chose an audio signal from my MP3 player.
Oh i see . But can you tell me please what is exactly is the use of the 7555 chip ?
jensenr30 (author)  looney1236 months ago
the 7555 generates the base radio frequency. The audio modulates that frequency so.
emran16129 months ago
why Audio + is also connected to GND? pls help bro.
jwilkerson jr.10 months ago
Actually transmits on a harmonic of the AM broadcast band. Very dirty square wave transmitter; but it kind of works as a simple proof of concept device.
pokooos11 months ago
For those who are asking for the npn transistor, use a 2n2222 transistor (because it's a RF transistor). it works good.
simonyu1 year ago
how do u use a breadboard?
jensenr30 (author)  simonyu1 year ago
^ here is a link that will explain it
simonyu1 year ago
can ordinary Apple earphones fit into the female jack?
jensenr30 (author)  simonyu1 year ago
yes. they are 1/8 inch audio jacks so they should work just fine.
-max-1 year ago
I have built one of these from my own design! it used the 555 chip and the input for audio was in between pin 3 and an inductor. only problem was range and saturation (I heard the music across all stations, especially the ones with the right harmonics.)
jensenr30 (author)  -max-1 year ago
I had similar results. I was able to hear the audio throughout the AM channels
M070RK1 year ago
Sorry if I've disturbed you, but.
When implemented circuit , I've discovered that it work only when I touch one of its parts
Although I put an antenna, how to rectify this problem: (
Perhaps it isn't grounded correctly? Connect a wire with an aligator clip attached to the board, then connect the other end to something metallic which touches the ground. See if that works.
jensenr30 (author)  M070RK1 year ago
I'm not sure
edz291 year ago
Sir.. i want to try your circuit.. i have one question, what type/name of NPN transistor did you used??
edz291 year ago
Sir.. i want to try your circuit.. i have one question, what type/name of NPN transistor did you used??
sk190719921 year ago
Which NPN Transistor to Used in Circuit
LSD31 year ago
jensen, Thanks for the info. I'm good at the solar stuff and doing what I need with the signal. I simply want a number of low level x-mitters with tunable frequencies. An ADAC will convet the frequency with a little tuning and provide the PLC with a usable 4-20ma. the rest is easy in identifying the unit which made the transmission. and locating which one was triggered. The signal source has less than a mile to transmit and 5ms would be enough. There is no line of sight. Forestation and topography prohibit that. I'm thinking AM band would work. Each unit would have independent solar power (already done) providing 9vdc @ 300ma 24/7. Any ideas??

jensenr30 (author)  LSD31 year ago
I'm not that great with radio stuff. This was just my attempt and (partial) success in designing a cheap, 5-10 cm radius AM radio transmitter.
Monkeyspit1 year ago
Do you have a bird's eye view of this project, for those of us that don't know how to read schematics?
M070RK1 year ago
How can I run at a higher frequency, 10 Mhz for example, :)
jensenr30 (author)  M070RK1 year ago
You may have to get something of higher quality than a simple 555.
I looked around and the highest frequency I could find was up to 2 MHz. :(

You might have to do something with some LC-circuits or something along those lines.

Hope this helped!
zali111 year ago
not good choice
jensenr30 (author)  zali111 year ago
as I say in the article, it isn't the best quality wise, but it works. and for a beginner, it is nice to get something that isn't too complicated that works because when things don't work, we get discouraged. :(
I'd rather do something simple that works than attempt something complex that leaves me feeling like I got nothing accomplished.
that isn't to say that you shouldn't strive to do meaningful, big, important things, but i guess what i'm trying to say is that it is good to start small :)
that is just my two cents though.
take it with a grain of salt.
jukees1 year ago
is this transmitting mono audio signal, or stereo?
i think it is mono.
jensenr30 (author)  jukees1 year ago
this is definitely only transmitting one signal. good question!

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