© 2010 Akula LLC, Jeremy R. Hertzberg, BS CMPE Switches and Relays Electro-mechanical transistor.
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Transcript of © 2010 Akula LLC, Jeremy R. Hertzberg, BS CMPE Switches and Relays Electro-mechanical transistor.
© 2010 Akula LLC, Jeremy R. Hertzberg, BS CMPE
The Switch◦SPST◦SPST Pushbutton NO◦SPDT
The Relay
Power up the board
© 2010 Akula LLC, Jeremy R. Hertzberg, BS CMPE
Switches
The simplest switch is the Off-On switch
Also known as the Single Pole Single Throw switch
AKA SPST
© 2010 Akula LLC, Jeremy R. Hertzberg, BS CMPE
SPST Pushbutton NO
This switch is Normally Open (NO) or Off
Once pushed it allows power to flow.
© 2010 Akula LLC, Jeremy R. Hertzberg, BS CMPE
Single Pole Double Throw switch
A SPDT switch is like a railroad switch,
It allows current to flow from one of two paths.
© 2010 Akula LLC, Jeremy R. Hertzberg, BS CMPE
The Relay
A Relay is a switch that is controlled by an electro magnet.
© 2010 Akula LLC, Jeremy R. Hertzberg, BS CMPE
When power is applied to the electro magnet, the switch changes state.
© 2010 Akula LLC, Jeremy R. Hertzberg, BS CMPE
When the power is shut off, the switch returns to its original state.
© 2010 Akula LLC, Jeremy R. Hertzberg, BS CMPE
Why Use a Relay?
First, the relay can be used to turn on a large voltage with a small one.
Second, it isolates the control circuit from the controlled circuit. In the event of a accident to the controlled circuit like a lightning strike, the control circuit is protected.
© 2010 Akula LLC, Jeremy R. Hertzberg, BS CMPE
What Happens Next?
One LED will light up when you power up the board.