This is a schematic of a IR transmitter circuit using IC. The IC used in this circuit is a famous timer IC NE555 which is working as an astable multivibrator in this circuit and producing a 38KHz frequency signal. The circuit starts to produce the signal through IR LED when we connect a 9V battery to the circuit
and this 38KHz signal can be received by an IR receiver of same frequency. The frequency can be adjusted by 1K potentionmeter for accuration.