Connecting Opto-Coupler to TIP107

Can I connect an opto-coupler to a TIP107 using this method instead of placing the resistor at the base of the TIP107? If I can do it this way, it will make my breadboard so much cleaner looking. If I had the components in hand I'd try it myself, but they are still in the mail. Thanks in advanced.

The 1K at the bottom will only prevent your PNP from fully turning on.
Connect the NPN emitter to Gnd.
Rest is okay.

Thanks for the answer

I'm missing something?

The 1K at the bottom will only prevent your PNP from fully turning on.
Connect the NPN emitter to Gnd.

Resistor in series with NPN emitter is limiting base PNP current, you can't remove it. 1k is good up to 2 A output, what is the load?

The picture is one leg of an isolated H-Bridge.

There is nothing wrong with the circuit as it stands. The resistor in the Emitter of the Opto transistor serves to "Bias" the NPN "Base" to a higher level (more light) necessary to activate or desensitize the base junction? for lack of a better word or in other words make the required light level higher to activate the opto-transistor. If you wish to make the device more sensitive split the resistor between collector and emitter. If you need more current from the TIP107 you can lower the value of the 1K resistor but keep in mind that unless you know the specific power dissipation capability of the Opto Keep the power dissipated by the opto transistor to approx 200 mW (P = I2/R) in order to not damage the opto transistor by exceeding the transistor's dissipation limit.

Doc

The resistor in the Emitter of the Opto transistor serves to "Bias" the NPN "Base" to a higher level (more light) necessary to activate or desensitize the base junction? for lack of a better word or in other words make the required light level higher to activate the opto-transistor. If you wish to make the device more sensitive split the resistor between collector and emitter.

Are we looking at the same drawing? Or basic electrical Kirgoph's law already overruled by "iPad - facebook" generation?

Are we looking at the same drawing? Or basic electrical Kirgoph's law already overruled by "iPad - facebook" generation?

Your reference is rather cryptic.
My statement is ALL about where the Emitter voltage of the Opto transistor is when the device starts conducting. Since when the light intensity from the LED increases enough to start the device conducting it will raise the emitter voltage, thus requiring more light to insure complete turn on of the transistor.

Doc

Since when the light intensity from the LED increases enough to start the device conducting it will raise the emitter voltage, thus requiring more light to insure complete turn on of the transistor.

This is not correct. Phototransistor works in saturation area, collector current mostly defined by LED's current, and practically doesn't change with emitter-collector voltage variation.

The resistor in the Emitter of the Opto transistor serves to "Bias" the NPN "Base" to a higher level

This is complete rubbish.

If you wish to make the device more sensitive split the resistor between collector and emitter.

The same here, emitter resistor serve only for current limiting , when phototransistor fully saturated or fails via collector-emitter breakdown. Collector of phototransistor loaded by base-emitter junction of the PNP, not 10k. which is only needed to cancel "dark" current of phototransistor and doesn't play any role in normal operation.