This Long range Infrared transmitter can emit pulsed IR rays up to 10 meters. This IR transmitter is ideal to use in Infrared receivers using Phototransistor or Photodiode as IR sensor.
The circuit is a simple Astable Multivibrator using IC NE555. Resistors R1, R2 and capacitor C1 fix the output frequency to 1 kHz. T1 is the Darlington high gain PNP transistor that drives two Infrared LEDs. Resistor R4 is the pull up resistor that keeps the base of T1 high for its proper working. By changing R2 with a 4.7K preset, output frequency can be changed. Red LED indicates whether the IR LED is working or not.
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