Hello everyone! i have a question about the 4N35 optocoupler and trying to find the input voltage (diode) on it! the datasheet notes a 7v revers voltage! thank you to light me!
That is reverse voltage and the LED will not light with reverse voltage.the datasheet notes a 7v revers voltage
Only to the extent that its voltage affects the determination of the value of the current-limiting resistor (or circuit).ok thanks to everybody! so on a diode input it doesnt matter the voltage only the mAmps are calculated!
Almost.....The chart in post #2 is showing the typical operating characteristic for VFwd (forward voltage (DROP)) vs the IFwd (Forward Current) across the LED. So you have to take the voltage drop across any current limiting resistor into account when calculating the resistor value to obtain a specific LED operating voltage/current.ok thanks to everybody! so on a diode input it doesnt matter the voltage only the mAmps are calculated!
That's if you use a resistor to give a constant current.In theory, an ideal current source has infinite source resistance, but you would have to make the source voltage infinitely large as well.
Just as an aside note, re the output, you can use either the emitter or collector output, i.e. inversion, sink or source.Hello everyone! i have a question about the 4N35 optocoupler and trying to find the input voltage
I'm curious about what 7 volt reverse voltage specification are you talking about? Which component can potentially be reverse biased?Note also that exceeding that 7 volt reverse voltage results in immediate destruction of the LED, leaving the device useless.
The LED.I'm curious about what 7 volt reverse voltage specification are you talking about? Which component can potentially be reverse biased?
OK the LED, but how does it get reversed biased in the circuit offered by @crutschow ?The LED.
In post #1 the TS comments about seeing a reverse voltage of 7 volts, and wonders about that. At some point I state that exceeding 7 volts reverse will destroy the LED. the diodes on LEDs do not have high reverse voltage limits and so are quite easily destroyed.The LED.
Well since the TS never provided a schematic of what he was doing so it would be hard to know what his observation means. I thought you were talking about the circuit in post #11. My mistake.In post #1 the TS comments about seeing a reverse voltage of 7 volts, and wonders about that. At some point I state that exceeding 7 volts reverse will destroy the LED. the diodes on LEDs do not have high reverse voltage limits and so are quite easily destroyed.
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