The presented simple infrared transmitter circuit design can be used in the form of an infrared remote control, with a frequency modulated tone, to operate a complementing IR receiver circuit.
How the Circuit Functions
The transmitting frequency is determined by C1 and adjusted using the trimpot 100k.
The transmitter LED must be of the infrared type and more power can be achieved by connecting two LEDs in series with a series 100 ohm limiting resistor (using no less than 22).
The supply voltage which becomes the operating voltage for the infrared transmitter can also be increased to 9V in order to compensate the presence of the LED resistor.
Hi,
I made this circuit and it won’t work.
Is everything correct in that drawing?
Everything is correct in the drawing. It is a simple oscillator circuit. Replace the LED with a speaker and check whether it is emitting a tone or not.
Please make sure the 47nF is not connected to the emitter of Q1….it is directly connected to R3.
Hi everyone, I am thinking of making a multiple channel IR transmitter and receiver without using any ic ,can you help me with that?
Hi! Can you please tell me for what are the bipolar transistors used for? Are they used as a switch?
Hi, yes the main application of BJTs or any type of transistor is like a switch, and also like an amplifier
Hi I assembled this circuit. Supply voltage is 5vdc and one IR LED from a TV remote control. I got 25cms range.
Currently I am using two seperate identical circuits for driving LEFT and RIGHT LED’s of an ” Ostacles avoiding robot toy car ” . I want to use single transmitter for two IR LED’s in series on 9VDC supply. What changes should I make…..?
( You have already explained 9v connection in the article.
But I didnot understand it. Can you please explain it some other way ….? )
Hi, I am glad you could make it….for using two LEDs you won’t have to change anything, just connect another LED in series with D1, and use 9V as the supply…may be 100 ohm could be changed to 150 ohms, that’s all