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 IP2
"+ going"
Input Switch


How the circuit works.....


The voltage at the output of this subsystem is 0 volts until the switch has been pressed. When the switch has been operated, it is said to have been made and the output voltage immediately rises to +9 volts. The switch shown is a push to make type. The resistor in series with it is known as a pull-down resistor. It is there to "pull" the output of the subsystem down to 0 volts when the switch has not been pressed. This is essential if you connect the subsystem to digital inputs of "logic" circuits or PIC's, as they need to see a high (+) or a low 0 volt (-) signal.
This module is sourcing the next subsystem as it is providing a positive voltage. The arrow head on the module indicates this positive voltage and its tail a negative voltage. In this example, when you connect the buzzer, you need to take its other contact back to the negative side of the power supply, as shown. By doing this you are making a complete circuit.

 

 

 

 

 

Circuit Diagram

 

 

 

 

Other examples of switches giving a "+ going" output voltage.