Motor Bike Brake Horn

The circuit can be operated from 4.5V to 12V DC or direct from the brake point of the motor-bike, Resistor R7 should be replaced with 1-ohm. 1/2W in case of an 8-ohm speaker. T5 is a driver transistor. C3 polarity can be reversed for a sudden off of the circuit.

The sound produced is like “Kiun, Kiun”.

circuit diagram of motor bike brake horn


Resistors (all ¼-watt, ± 5% Carbon)

R1, R7 = 2.2 KΩ

R2, R4 = 820 Ω

R3, R5 = 470 Ω

R6 = 4.7 KΩ

R8 = 10 KΩ

R9 = 4.7 Ω, 0.5W


C1 = 22 µF/25v

C2 = 4.7 µF/63V

C3 = 100v/16V

C4 = 0.047 µF

C5 = 0.01 µF


T1 – T4 = BC148B

T5 = SL100


LS1 = 4Ω speaker

7 thoughts on “Motor Bike Brake Horn”

  1. Hi there,
    Just some clarification
    Is R9 meant to be 4.7K ohm, C3 100 uF and what are the voltages for C4 and C5.


  2. it is a very good project suggetion for seriousness about any one on the road who riding or walking ,also for awairness of traffic.can you send me the circuit digram.

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