Back-up alarm is a device originally intended to warn passers-by of a vehicle moving in reverse. It is widely used in trucks, buses and construction vehicles. The alarm is connected in the circuit of reversing light. Our products is small in size, flexible in installation and can be integrated with other functions.

Our products can realize voice bleeps and vocal broadcasting, and some products can realize smart self voice adjusting function.

Working Principle of Reversing Buzzer

The backing buzzer has two sets of coils L1 and L2. The coil L2 circuit is in series with the capacitor. When the buzzer works, the two coils are energized at the same time. Because the current is equal and opposite, the coil flux cancels each other and the contacts are closed. As the capacitor continues to charge, the voltage at both ends gradually increases, the current of coil L2 is reduced, the magnetic flux of coil L1 increases the suction contact, the circuit is interrupted, and the buzzer does not work. When the voltage at both ends of the capacitor is zero, the contacts are re-closed and the buzzer is re-activated, and the capacitor is re-charged. This repeated cycle, backing buzzer will emit intermittent "beep, beep" sound. Now the reverse buzzer also uses IC chip, the structure is simpler.

Cautions for Use of Back-up Buzzer

1. The production date of backing buzzer should be within half a year, otherwise it will be rejected.
2. When testing the starting current, the starting current is the loop current when the buzzer reaches the standard sound.
3. In the test method of loop potentiometer, because of the small circuit current, the voltage at both ends of the potentiometer is neglected, so the output voltage of the power supply is the voltage added by buzzer.