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Transistor working theory Consist of two diodes back to back. By controlling states of the two diodes, we can control the switching of the transistor (ON-Off). Look at this program to get the idea !!!!
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2nd session of R&A Transistors & couplers
Agenda
• Transistors as switch.• Transistor testing.• Opt couplers.• Relays.• Simulation with Proteus 7
professional program.
Transistor working theory
• Consist of two diodes back to back.• By controlling states of the two diodes ,
we can control the switching of the transistor (ON-Off).• Look at this program to get the idea !!!!
Transistor OFF state
Transistor ON state
Transistor testing
Opt Couplers • Opt couplers make an isolation between interfaces of
two circuits.
• typically consist of a gallium arsenideLED (light-emitting diode) and an optical receiver such As phototransistor or light-triggered diac . The two areseparated by a transparent barrier which blocks anyelectrical current flow between the two, but does allow The passage of light.
)AC/DC (Isolation
DC/DC Converter
6 Pins Package
8 Pins Package
Relays• An electromechanical or solid-state device
operated by variations in the input which, in turn, operate or control other devices connected to the output. They are used in a wide variety of applications throughout industry, such as in telephone exchanges, digital computers, motor and sequencing controls, and automation systems.
• Bins configuration (No,Nc,C,Coil).
Simple circuit
Relays -5 Pins
(DPDT) Relays -8 Pins
Controlling Motor Direction
Question!!!!!???
• When you will use Relay instead of Opt coupler in your application and vise versa??!!!
SimulationProteus 7 Program
Thank you
Introduced by• Eng. Mustafa Ahmed Hemdan.• Chairman of Robotics &Automation Chapter• Communications & Electronics department.• E-mail: [email protected]• Mob: +20173220460
• Our blog : • http://rastsc.wordpress.com• Our group on facebook :• Robotics & Automation Chapter
