SIMPLE TOUCH SENSITIVE SWITCH CIRCUIT

SIMPLE TOUCH SWITCH

Now i am going to introduce you a SIMPLE TOUCH SENSITIVE SWITCH.

I hope you enjoyed my previous articles about

• Water Tank Overflow Alarm
  
  
• Rain Detector Alarm
  

Now take a look on Touch sensitive Switch. It is much similar to previous one and the circuit diagram is quite same. The Circuit doesn't seems to use any kind of complex multivibrators nor any sensitive electronic components. The Circuit works under the theory of Darlington Pair, as we discussed in my last posts the Darlington Pair will trigger if we applying an Impedence to its input terminals. In the last two posts the connecting medium is water (with Impedence) and now its our Skin. Yeah SKIN is a conducting medium with high Resistance (about 1Mohms). When we touch across the two input terminals the Darlington Pair gets activated which will Switch the Alarming section and generate the tone.

CIRCUIT DIAGRAM OF TOUCH SENSITIVE SWITCH

WORKING PRINCIPLE OF TOUCH SWITCH

If you want to know about how a Darlington paired circuit works you can check our previous articles
Please Note:-

• The circuit Alarms when you touch across the input terminals.
  So try to Keep them as close as possible.
  
  
• You can replace the Alarming section with a LED bulb to demonstrate the working.
  
  
• By Earthing any one of the input terminals you can make it easy to use.
  ie; Touching the unearthed terminals cause the circuit to trigger.
  
• 
  
• Special Note:- if you are going to use single terminal Touch Switch, you should be Bare footed to make the circuit complete.
  
  
• By the application of Single Terminal Touch Switch you can use it as

  TOUCH SENSITIVE SECURITY ALARM

  .
  Use one end on the metal plate of your door knob while the other earthed.
  
  

How to Earth an input Terminal?
Here, the term 'Earthing' is used to represent, keeping a conducting material in direct contact with floor.
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