This is a circuit diagram for a 'Travel touch alarm'
Travel Touch Alarm | Circuit Project Electronic
Q1) The 555 is activated when pin 2 goes to low voltage. But why does it do this when someone touches the touch plate?
In this circuit **broken link removed**
Q2) there is another touch plate, what exactly happens when the plate is touched here?
I can understand a touch mechanism where your finger is completing the circuit at a high resistance, but in the two examples above this isn't the case, there is no circuit completion - so what exactly is happening?
Travel Touch Alarm | Circuit Project Electronic
Q1) The 555 is activated when pin 2 goes to low voltage. But why does it do this when someone touches the touch plate?
In this circuit **broken link removed**
Q2) there is another touch plate, what exactly happens when the plate is touched here?
I can understand a touch mechanism where your finger is completing the circuit at a high resistance, but in the two examples above this isn't the case, there is no circuit completion - so what exactly is happening?