Hi, I'm Debarun! 👋

Hello my name is Debarun Chakrabortty. I am a pre final year B-Tech student at IIT ISM Dhanbad from Electronics and Communication Engineering department.Some of my areas of intrest are Robotics,IOT,Blockchain Devlopment etc.

Darlington Pair Touch Switch

• A Darlington pair is a configuration of two bipolar junction transistors (BJTs) connected together to amplify current. It is commonly used in various electronic circuits for its high current gain. While it is not typically used as a touch-sensitive switch, it can be employed in conjunction with other components to create a touch-sensitive switch circuit.

• The key advantage of the Darlington pair is its high current gain. The current gain of a single transistor is typically denoted by β (beta). In a Darlington pair, the current gain is the product of the individual transistor gains. So, if the first transistor (Q1) has a current gain of β1 and the second transistor (Q2) has a current gain of β2, the overall current gain of the Darlington pair is approximately β1 x β2.

Working Principle

• A transistor has 3 pins, one is the collector, one is the base and one is the emitter. The base is like a switch activated by either a negative or positive charge depending on what type of transistor you are using. Once the base is activated, it allows current to flow from the collector to the emitter, amplifying the current.

• With this concept, since our fingers store charge, we can use that charge to activate our transistor with its collector connected to a power source. Since the emitted charge is still extremely low, we can use this new charge to switch on another transistor with its collector connected to the same power source as previously. The new emitted current is large enough to make a LED glow bright before it returns to the ground.

Components Used

• BC547 Transistor(2)
• LED(1)
• Resistors-470 ohm(2)
• Constant DC power source
• connecting wires and bread board

Future Prospects

• The Darlington pair finds applications in various circuits where high current gain is required, such as motor drivers, power regulators, and audio amplifiers. It can also be used for switching applications where the input current is relatively low, and the output current needs to be amplified.

• The sensitivity of this contraption can be increased by changing the components and may find application in indutrial touch switches along with pressure sensitive touch pads.