Take the typical forward voltage of 1.2V and the current of 20mA. With these parameters, you can estimate the R2 value in the network SENSOR_OUT, R2, PC817 pin1 of your drawing. This parameter is measured with the current through the photodiode as specified in column Conditions, \$I_F=20mA\$.
Photodiode voltage (values in columns MIN, TYP, MAX) is the voltage drop across the IR photodiode. Table Electro-optical Characteristics (page 4) specifies the photodiode current and forward voltage in the first row, where the column Parameter content is Forward Voltage. You can read UTMEL's (SHARP's) datasheet for PC817 optocoupler online. both the ground must be ISOLATED.Manufacturers/suppliers of electronic components describe their products in datasheets. NOTE: Do not connect the ground of the control circuit and switch circuit together. One pull-down resistor is connected between the gate and ground to avoid false triggering.
The positive power supply is connected to the collector (pin 5) of the optocoupler where the emitter is connected to the gate of MOSFET. The current limiter on the other side depends upon your circuit and operating voltage. You can also use a higher value of the resistor but not a lower one. R = 380-ohm is the minimum value of the resistor we have to use on the input side. This is the voltage dropout by a resistor to protect the LED of the optocoupler now let’s calculate the value of the resistor using Ohm’s Law Let’s calculate the value of the resistor One current limiting resistor is connected between Arduino pin 9 and optocoupler pin 1 to protect LED from burnout. The reason for using a PWM pin is to vary voltage but you can use a digital pin instead according to your requirement. Anode is connected to PWM pin 9 of Arduino PWM (you can use any other PWM pin or other according to your requirement). MCT2E is 6 pin optocoupler but here we are using only 4 pins as shown in the figure. It is built around Arduino NANO, MCT2E Optocoupler, MOSFET, resistor, and other few components. The circuit of Arduino and optocoupler interfacing is shown in figure 2. For this purpose, we can use an optocoupler.Ĭircuit Description of Interfacing Optocoupler with Arduino Normally, the Gate to Source voltage (V GS) of MOSFET or IGBT is greater than 5V so we cannot trigger the gate directly from the microcontroller.
#Opto isolator inpug ic how to#
You can also check “ How to make Relay Switch Circuit”.
It provides isolation between the control circuit and power switching and saves the control circuit from high-voltage transient or surge voltage usually generated from Inductive load like Motor, relay, etc.There are various reasons for using Optocoupler for switching, some are listed below The LASCR output coupler for figure 1(c) can be used in applications where a low-level input voltage is required to latch a high voltage relay for activating some kind of electro-mechanical device. When LED is forward-biased, the light produced by it is transferred to the phototransistor when is turned ON thereby producing current through the external load.įigure 1(b) shows a Darlington transistor coupler which is used when increased output current capability is needed beyond that provided by the phototransistor output. Such isolators allow circuits to interface with different voltage levels and grounds, etc.Īn optocoupler or optical isolator consists of a light source such as LED and a photodetector such as a phototransistor as shown in figure 1(a) and is available in a standard IC package. The usual purpose of isolation is to protect from high-voltage transient, surge voltages, and low-level electrical noise that could result in an erroneous output or damage to the device. Optocouplers or optical isolators are designed to electrically isolate one circuit from another while allowing one circuit to control the other.
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