TOUCH ME NOT TOUCH ACTIVATED SWITCH Sharon Abraham 311

Criteria & Chosen Circuit  Possible to build Physical Circuit  Parts learnt about in class  Simple enough to model and understand  Learn about real circuit development  Get A in class  Chose Touch Activated Switch  Meets criteria  Interesting concepts

Circuit

Problems / Changes Circuit had both source and sink How to model human touch Removed one piece – used only sink Modeled as capacitor and pulse voltage source

Final Circuit Model

Simulation

Human Body Capacitance Sizable Capacitance Change Environmental Factors

Analysis Oscillator 20 kHz Shmitt Triggers Rails – Voltage sources

Oscillator

High Resistance Zero Current

Transistor – Diode – Only positive voltage

Amplifies Signal

Conclusion Circuit works as was expected

Uses Modifications Uses Modifications Elevator buttons Pool sensor Touch activated lamp - Addition of Flip Flops Alarm System - Output load is a siren