1. J

    Choosing of resistor value at input of optocoupler (EL 817)..

    Hello all I'm trying to make a small circuit in which i have to choose the resistance value.. can someone tell me how to choose the resistor value at the input of Optocoupler IC. And my input voltage is 3.3V .. and current 25mili amps ..
  2. K

    Heat plate triac control, R2 value

    I am not sure how to calculate the triac R2 value. Real componets are: BTA12-600CWRG (Triac) and KMOC3063 (Zero-Cross Triac driver photocoupler, IFT 5mA). Optocoupler input will by PWM controlled by 3.3V MCU (ATtiny1604). Imax R1 = 5.2 mA and Imax R2 = 50 mA (in LTspice simulation).
  3. S

    Can someone help me please!!!? IRFZ44n MOSFET heats up driving TEC Peltier

    Hello everyone, I would really appreciate if you could help me Im making a mini fridge controller (PID), using a 4n25 optocoupler, an IRFZ44n Mosfet and a tec peltier I connect it to a 12v and 3 A and arduino 5v As soon as the arduino code is uploaded and I connect it, the mosfet starts to...
  4. J

    Using Transistor Optocoupler for level shifting

    Hi Im using a NPN Transistor output Optocoupler (Toshiba TLP290) as a level shifter. I have a source squarewave and a constant current chip (20mA) in series to drive the Optocouplers internal LED. The idea is that the constant current chip will allow the optocoupler to be safely and...
  5. Luiz Fernando Vieira

    triac optocoupler with dual output

    I'm having trouble finding a tric coupled photo with two independent outputs. Diode input can be the same, it is not necessary if 2 separate diodes. Someone could indicate a specific model, website or name of the component.
  6. T

    Optocoupler Input switch problem

    I am having a problem switching the positive input of an optocoupler to ground using a mosfet. Please look at the schematic and plots I did. The mosfet gate is getting 5V, but the output attached to the 1.5K input resistor doesn't go to 0V?
  7. Genosphere

    Trouble: Simulator expectations vs constructed circuit; 555timer.

    So I am having some trouble building the circuit I had built in a sim, several to be exact, which all seemed to work the way I wanted them to. Now that I have built the circuit on a board, Im not getting the results expected. Checked wiring and and parts, things look ok. Odds are I have missed...
  8. K

    I need help with my circuit (optocoupler, transistor, relay)

    Hello, i've got a newbie question, i hope some of you more experienced guys can give me an answer. I've recreated a simple circuit, that closes relay contacts using optocoupler and transistor, just for fun and i've found out that it's not working, after some time i've succeded to get the circuit...
  9. Generation

    The ohmmeter shows wrong output resistance of an optocoupler in Proteus

    In the attached Proteus circuit I used optocouplers NSL-32SR3. Its dependence on the LED current is depicted in the attached graph. Unfortunately for some reason the ohhmeters show always 100MOhms, and it doesn't matter on the applied to LED current.
  10. Generation

    Is it valid to create your own model of optocoupler in Proteus?

    I'm modelling an all-pass filter which uses optocouplers with linear output resistance characteristics. The scheme is in the attached file. I was suggested to use any of these optocouplers...