Hi, I am very passionate about electronic. I need help on suitable RF Circuit for RC car toys. I have googled it but i came out with lot of them and i do not know which one to use. I need to design a transmitter and receiver circuit. I know that i need a tuning circuit such as variable capacitor (trimmer) and inductor (coil). i bought a 22pf trimmer and ferrite rod and enamelled copper wire to make an inductor for rf tuner. I need help.

Thank

g3xoi is right.

You'll also need to learn about oscillators, how to launch power out of them to turn them into transmitter, receiver design and the materials used in tuned circuits (ferrite rods are useless above a couple of MHz).

Some useful info:

http://talkingelectronics.com/...ers/27MHzLinks-1.html

but needs more background and help on how some of it works and on construction.

You could get a copy of LTspiceIV (http://www.linear.com/designtools/software/), learn to drive that and then you can model and simulate the various circuits shown above to help understand how they work.

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Andy Fierman

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http://signality.co.uk
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Just happened to see your request for info on RF circuit for toy cars. I recently wanted a control circuit for a Gauge 1 model train engine. I ended up using 433MHz Tx/Rx modules from Quasar UK ltd. You can Google them. Look at the am modules. They have a range of about 50m.

RF Solutions is another company making Tx/Rx modules, but are a bit more expensive. However they also make an encoder and decoder which can be used with the Quasar modules. The encoder has 4 inputs and 1 output which drives the Tx, and the Rx provides an input to the decoder to get the 4 outputs. With a small microprocessor I was able to get Forward, Reverse, SlowDown and Emergency Stop. For a model car you would need to generate a variable pwm signal to control a servo.