Liebert TM-10098 Basic Operation of the Opto-Isolator, Output Opto-Isolator, Input Opto-Isolator

Models: TM-10098

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Basic Operation of the Opto-Isolator

iCOM Controls Training and Service Manual

Basic Operation of the Opto-Isolator

The purpose of the opto-isolator is to provide isolation of two voltage sources. This allows a DC voltage source to activate an AC voltage load device or allows an AC voltage source to provide a DC signal.

We are working with two types of circuits, an input and an output. Therefore, we require two types of opto-isolators (referred to as optos).

The output opto uses a DC voltage source to activate a Light Emitting Diode (LED) internal to the IC chip. This causes a triac, also internal to the IC chip, to switch ON allowing current to flow to the AC load device.

LED

DC

Sourc

AC Sourc

LED

DC

Sourc

AC Sourc

No Current Flow

Current Flow

Output Opto-Isolator

The input opto uses an AC voltage source to activate dual LEDs and turn on a transistor to pass the DC voltage and allow current to flow.

Dual LEDs

AC

Sourc

DC Sourc

Dual LEDs

AC

Sourc

DC Sourc

No Current Flow

Current Flow

Input Opto-Isolator

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Page 119
Image 119
Liebert TM-10098 service manual Basic Operation of the Opto-Isolator, Output Opto-Isolator, Input Opto-Isolator