الوصف

  Name:WE***3 Ambulance Alarm        

CODE NO:************0        

 Weight:0.**2KG
 The circuit includes two HA*7 **5, both of them work in status of multi-vibrator but with two different operating frequencies . The frequency of waveform of IC 2 is control led by low-frequency square waveform of IC1. W hen the waveform of IC1 is at low voltage , the oscillating frequency of IC2 is low; otherwise the oscillating frequency of IC2 is high . Therefore sound of “wu wa“ is coming from speaker. The sound effect can be changed by adjusting values R2, C1 or R5, C2. The operating voltage of this circuit is 6V. It requires four 1.5V batteries.