What is an opto coupler and how isolation is achieved by optical coupling therein discuss its applications in instrumentation?
Definition: An optocoupler or optoelectronic coupler is an electronic component that basically acts as an interface between the two separate circuits with different voltage levels. Optocouplers are common component by which electrical isolation can be supplied between the input and output source.
What is opto coupler and explain its working principle?
An optocoupler is an optical link and it connects two circuits via this link. The optical link is contained within a chip. A Light Emitting Diode inside the chip shines on a photo-diode, photo-transistor or other photo device. When the photo device sees illumination, the resistance between its terminals reduces.
How does an opto coupler work with an isolation gap?
The gray box is a diagram of the HCPL2631 Opto-Coupler. Each input LED of the opto-coupler has a corresponding ‘open-collector’ output. When current flows through the internal optics, it transmits light across the isolation gap, and turns the output transistor ‘on’.
How much voltage can an opto coupler handle?
In present commercial market, we can buy Opto-coupler with 10 kV to 20 kV input to output withstand voltage capacity, with a specification of 25 kV / uS voltage transients. This the internal structure of the opto-coupler.
How is an optocoupler used in a circuit?
In a circuit, optocoupler is used to switching a system using a digital signal or using a very low voltage, but if there is spikes of voltage or surge current occurs then the whole output circuit will be non-affected because the optocoupler got damaged only and stops the passes the current to next portion.
Which is better photodiode optocoupler or phototransistor opto-coupler?
photodiode Optocouplers are better than phototransistor optocoupler in a linear relationship between the current and the light. Although phototransistor optocoupler can pass the analog audio signals at wide frequencies by varying the LED beam that goes to the BASE of the phototransistor.