University of Nottingham Electromechanical devices MM2EMD Lecture 7 – Transistors - Switching high voltage things on with a low voltage Dr. Roderick MacKenzie
[email protected] Summer 2015 @rcimackenzie Released under Outline of the lecture •No recap of last lecture :) •Transistor basics •Relays (Mechanical transistor) •NPN Bipolar Junction Transistors •PNP Bipolar Junction Transistors •MOSFETs •Push pull pairs to drive MOSFETs •One last thing •Summary 2 Roderick MacKenzie MM2EMD Electromechanical devices Outline of the lecture •No recap of last lecture :) •Transistor basics •Relays (Mechanical transistor) •NPN Bipolar Junction Transistors •PNP Bipolar Junction Transistors •MOSFETs •Push pull pairs to drive MOSFETs •One last thing •Summary 3 Roderick MacKenzie MM2EMD Electromechanical devices Roderick MacKenzie Roderick electrical devices suchas motors. high voltage control electronics • This lecture is making low voltageThis lecture Think back to lecture 1. lecture Think backto Dave Jones Smart Electronic Circuits (low voltage) Circuits voltage) (high S.J. de Waard Simple Simple Electrical MM2EMD Electromechanical devices 4 Think about an AND gate chip And gate Biro •Look at the tiny thin pins which are used to carry current in and out of the chip. •These pins can supply 25 mA @ 5V at the most. 5 Roderick MacKenzie MM2EMD Electromechanical devices But why is this? i •If we take the top off the chip h p o with acid. G ● Look how much small the actual chip is and look at the tiny bond wires (25 mA @ 5V max!!!) 6 Roderick MacKenzie MM2EMD Electromechanical devices Roderick MacKenzie Roderick 500 V • It needsIt Now think about this motor. this about Now think to run.to 10 Amps 10 at CMBJ the current.