Just to clarify: Do you want the transmitter to run on unregulated 12V, regulated 12V, or regulated 5V produced by a 12V battery?
John
i want to make regulated 5V produced by a 12V battery..... but as i know..im afraid the output regulated voltage is not accurately get 5v ....it must be around 4.5v to 4.8v.... so it must affect the frequency of the infrared.....how about this....