An optoelectronic device which combines an optical transmitter and receiver in a single package; commonly used in galvanic-isolated control applications such as power supplies.

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285 views

Driving a 24V isolated load from a 3.3V MCU

I am looking to drive a 12-24V purely resistive load from a 3.3V MCU. I would like to use an opto-isolator to separate the circuits electrically. I've drawn up the following circuit, but I'm not ...
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1answer
47 views

Is it safe to use Vcc from processor side or use another supply

I have a Toradex Carrier Board. It has few GPIO pins. I need to use them as inputs. In our application we will give 12v input but as the pins can only take 3.3v so I have to design a simple board ...
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28 views

Optocoupler in reverse-active mode

I was recently reminded that BJTs can be used in reverse active mode. Can somebody enlighten me whether and to what extent the same is true for optocouplers? Do the same limitations apply to reverse ...
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148 views

Optocoupler high side vs low side switch

I have a NPN Darlington Optocoupler that I have been using for low side switching. I was wondering if it would be okay to also use as a high side switch? Optocoupler Datasheet simulate this ...
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0answers
756 views

Using optoisolator and triac with mcu to switch light on/off--need low power alternative

I'm using the schematic below to control a lamp (light bulb) with a microcontroller and I'm running the mcu (and moc3010) off of AA batteries. I just realized the moc3010 has an LED in it that needs ...
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39 views

FET Default on, Turn off with Optocoupler

I am relatively new to electronics and having trouble designing a circuit for a redundant power supply, which I would like to switch to battery if the voltage regulator turns off. This will be ...
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0answers
56 views

Adding resistor in parallel to digipot

I'm trying to control a device using a digital potentiometer (AD5245S). In my application I can't tie the low-ref of the potentiometer and ground, so I'm using an I2C optical isolator (ISO1541) to ...
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0answers
120 views

Voltage drop problem?

I made a circuit using PC817 optocoupler. On its 1st pin, i gave 3.3v, 2nd pin was ground. 3rd pin was 12v and on 4th pin i used a pull down resistor with resistor ...
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55 views

Driving an optoisolator with a 2N2222?

I'm driving an opto-isolated MOSFET gate driver with a 2n2222 transistor from a 3.3V microcontroller (TI Tiva C, 2-8mA max per pin). The IX3108G that I selected needs 10-16mA to be driven ON. This ...
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218 views

Using an optocoupler to put an AC signal on a DC bias

Expanding from this question Can an opto-isolated input be analog?: Can you use an optocoupler to take an AC signal and attach it to a DC bias? More specifically, can you take something like a 1V ...
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845 views

Can You Drive Back-To-Back MOSFETs (aka a Solid State Relay) Without Using An Optocoupler?

I was wondering if there was any way of driving back-to-back MOSFETs (with their sources and gates tied together as shown in the following image) without using an optocoupler? The reason is that ...
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40 views

what is the best way to protect sinking inputs

I have a controller with sinking inputs ( should be grounded to activate) , I will use the system in a noisy environment, I want to protect these inputs from EMI and voltage spikes, what is the best ...
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139 views

220V AC Light Dimming(triac H11AA1, MOC3052-M)?

Could I use triac H11AA1 and MOC3052-M to control 220VAC with arduino? I am new to electronics and I am not sure if that components can handle the voltage... Also could you show me some circuit with ...
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0answers
80 views

How to isolate Data / GND between WS2811 LED IC and MCU

How do you isolate the Data and GND lines between an MCU and a WS2811 LED Driver IC? The W2811 is another system that I will be interfacing and need to maximise protection to this. Bandwidth is not ...
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77 views

How do i write if-else control statements in ngspice? the syntax does not seem to the same as that of pspice

I downloaded a pspice module from the CEL website which includes the command: ...