Current Part:
2x TIP142 NPN Transistor
2x 2n2222 NPN Transistor
2x 1kΩ Resistors
2x 10kΩ Resistors
2x Dual Terminal Block
Triple Terminal Block
Dual Layer PC Board
Ferric Chloride Etchant
Clothing Iron
Platic Container
Push Buttons
DC Motor
Soldering Iron
Solder
Power Drill
Laser Printer
Glossy Paper
Parts List Details
All the parts listed above are used in this tutorial and serve a specific purpose. The main parts are described in more detail below to give you an idea of why we need them and what it is that they do.
TIP147 and TIP142
These transistor pairs are high power (125 Watt) and high current (10A) darlington pair transistors. One is an NPN type transistor, the other is PNP. They are made to fit together specifically for H-Bridge configurations. When you see the scheamtic, it will be somewhat obvious how these pairs just fit together.
2n2222 NPN Transistor
These simple 2n2222 transistors are used as buffers beteween the digital on/off side and the analog motor control side of the circuits. A simple digital signal into the 2n2222 tells the h-bridge to go forward or backwards, the theory section will go more into the details of how the h-bridge works.
1kΩ Resistors, 10kΩ
The 10kΩ resistors are used as current limiting 'buffers' between the digital and analog portions of this circuit. They will help protect against potential damage to any digital circuits controller the h-bridge. The 1kΩ resistors are also current limiting resistors so that the 2n2222 does not get damaged when it is switched on.
Dual Terminal Block and Triple Terminal Block
Two dual terminal blocks are used to connect the motor and the power supply to the H-bridge circuit. The triple terminal block is used to connect the digital control signals: Forward/Reverse/Ground to the h-bridge.
DC Motor
DC motors are one of the simplest types of motors and we'll be controlling one of those in this tutorial. I have a few DC motors that I will use to test the circuit, anything that doesn't require more than 10A to move will do. This is probably any motor you can find that costs less than $50.