Monday, 18 Dec 2017

    3V Mini Alarm

Description :
This alarm can made sound with 2 tones . The higher or low of the tone can be arrange by turn trimpotentiometer.

Specification :
- Input voltage : 3V - 6V DC (Battery)
- Using speaker 1 W 8 Ohm
- Battery polarity

The Procedure :
This alarm work based on positive feedback. Output sign that fit on speaker be feedback again to transistor basis TR1 with frequency filter shaped by R1C3. So that caused sound on speaker. During feed back process also happened empties and filling condenser 100 uF. This process caused up-down frequency.

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