High Quality FM Transmitter Circuit

This FM transmitter circuit is useful for transmitting music around your house. It has adjustable power and does not take many parts. The circuit has two parts, a transistor circuit and an amplifier circuit. There is also an included circuit for a power meter that you can hook up.

I think this circuit does a good job at keeping the circuit noise low while also giving you options on power output.

(source – http://electronics-diy.com/tx300.php )

1.5 Volt FM Transmitter Circuit

This 1.5 volt transmitter circuit is a very basic FM transmitter circuit. You can build it with a minimum of components.

These are fun projects to build with your kids so that they can see how fm transmitters work. FM transmitters have many similarities. A place for input of the signal and then different options for rebroadcast of the signal.  The nice thing about this transmitter is that it doesn’t take up too much space.

(source – http://www.cappels.org/dproj/FMdist/fmdis.htm)

2 Transistor FM Transmitter Circuit

Here is a two transistor FM transmitter circuit. I did some experimenting with this circuit and was initially looking for an FM transmitter that had a bit more power.

However, that being said, this doesn’t have many parts. If you transition from this two transistor FM transmitter to a 4 transistor, you will get a bump up in power. Check out my site here for some strong FM transmitters. Here is the source for this article (http://www.zen22142.zen.co.uk/Circuits/rf/2bjttx.htm)

Low Power 2 Transistor FM Transmitter

This is a low power 2 transistor fm transmitter. It is not the best quality transmitter but doesn’t take too long to build and doesn’t have too many parts. If you would like a better fm transmitter, then look for one of the more complext ones listed here.

This fm transmitter takes about 20 parts and is powered by a 9 volt battery. It can be affected by the electricity in a person’s body, so that being said, this does not make for a good personnel microphone or bugging device.

(source – http://www.zen22142.zen.co.uk/Circuits/rf/2bjttx.htm)

500 mW FM transmitter circuit

Are you looking for a somewhat difficult FM transmitter to build. This one might be right up your alley. This is a 500 MW FM transmitter. While 500 MW doesn’t sound like a lot of power, that is a good deal more than most of the FM transmitters listed on this site. I’ve listed the details at the end of this article. Before building, check your building checklist, do you have:

  • A good soldering iron – I use a Hakko soldering iron and it works great. It is good to buy a soldering iron that has a variable temperature setting on it. That helps you get the heat right for melting solder.
  • A breadboard for prototyping. – I use one from Radio Shack which works well.
  • A steady supply of patience.

If so, then here is the link to get you started. Happy building.

http://electronics-diy.com/tx500.php

FM Transmitter Circuits

Here is a collection of FM transmitter circuits that are easy to build. I went through each of these when I was building this list and checked them to see how easy they were to build. They require a minimum of components and don’t cost much to build. When you purchase your parts, order more than one of the same part. That way you can experiment with different builds on these fm transmitters. Before I list out the fm transmitters, what actually does an fm transmitter do. It basically picks up sound from a source, (this can be a microphone or some other input device). Don’t limit yourself to thinking that you need to have a microphone pick up your sound. You can also use a telephone (which is illegal of course), but for experimenting is an option. Just don’t break the law! Here are the fm transmitter circuits: #1 – Miniature FM Transmitter Circuit I like this small circuit because it doesn’t take many parts: http://www.uoguelph.ca/~antoon/circ/fmt1.htm #2 – Miniature FM Voice Transmitter Circuit This is a good circuit in the sense that you don’t have to have a large 9 volt battery attached to it. If you want to create a spy circuit, the idea is to keep it small so that it cannot be seen. This is a good option for that since it can use a 3 volt battery. You can take two 1.5 volt batteries and put them together to get the 3 volts. http://www.uoguelph.ca/~antoon/circ/fmt2.htm #3 – Two transistor FM Transmitter Circuit Two transistor circuits are very popular and I would say that most of the FM circuits I have seen are based off of a two circuit design. http://www.uoguelph.ca/~antoon/circ/fmt3.htm #4 – Miniature spy circuit using FET’s. There’s not a lot of detail on this circuit, so I’m afraid I can’t add much to its explanation. However, here is the circuit if you are interested. http://www.uoguelph.ca/~antoon/circ/uspy.htm

Shortwave Listening Device Circuit

When they built the US embassy in Russia, they discovered numerous listening devices and bugs all throughout the building. Many of these were embedded right into the concrete. It is a wonder that they didn’t block up all the radio bands for the whole area around there with all of those listening bugs.

There are several key requirements to building a good listening device. First off, it has to have a clear transmission. Secondly, it can’t be very large. For this reason, you can use shortwave transmissions. However, be clear to note here that this is illegal in some areas and that this article is merely for illustrative purposes only.  For this spy circuit, you will need some diodes, some transistors, and a microphone.

One thing that is helpful is to buy many of the same part or a batch of parts when you order from one of the major parts supply stores. That way, you can build several of these circuits or find out what you want to have in your order and combine your parts to make one large order. I like to order from Digikey mainly.

http://www.uoguelph.ca/~antoon/circ/uspy2.htm