Related posts

Feature

- Ding dong doorbell switch s1 is push button switch on the door, without press the switch, the capacitance cannot be connected is not recharged, and capacitance voltage of 0 v, the reset has been in a low level condition, leading to the speaker doesn't work. - When closed switch s1, the VCC current through the diode for capacitor charging, make its both ends of the voltage, and reset voltage also began to rise gradually. - When the voltage of the capacitance increased to higher levels, namely
Item will be shipped from China,20-30 days delivery