Collector-base voltage (IE = 0). BD BD BD BD The device characteristics and parameters in this data sheet can and do vary. BD Transistor Datasheet pdf, BD Equivalent. Parameters and Characteristics. BD Bourns Darlington Transistors W NPN Silicon datasheet, inventory, & pricing.

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Mar 5, 1, Jul 21, 2. No, create an account now. I’ve learned quite a bit here, but I can put this project at rest and tidy up now and focus on other things again. Do you already have an account?

OK thank you all for your thoughts on this. Jul 21, 1. Are you referring to R3? Will this work if you don’t have satasheet way to stop the LEDs quickly? Nov 13, Discussion in ‘ General Electronics Chat ‘ started by roukeJul 21, Jul 21, 7 0. How are you with mosfets?

I’m trying to make a flash slave as in the attached diagram. Without it the current through the opto-transistor at ambient light is sufficient to saturate the base of the darlington, and the LEDs are always on.

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But I think that’s what you’re saying albeit in other words ;- However, if R1 and R2 are high enough, the current through the base of the darlington would also be limited to a safe level. I’m a newbie The recommended current through the LEDs is 20mA and the max mA OK for a short flashhence the smaller resistors when the system is in flash mode. And using the hot accessory shoe would be an option, but I like the challenge of wireless, dataxheet so far B6d49 not yet convinced that using the hot shoe would solve datahseet problems I’m encountering here.

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Your name or email address: I may be wrong – honestly, I’m not sure. You suggested a 22k in series with the trim pot meter, and none in series with the opto-transistor. Really don’t think you are going to get that circuit to respond fast enough.

Sep 24, 2, As you could see from my pictures, the unit is a rectangular circuit board that slides in a Cokin filter holder with the LEDS facing forward and the opto-transistor mounted on the reverse side of the circuit board, facing the built-in flash. You size R3 to limit the total opto current to 0. First measure the current through the opto transistor in ambient lighting conditions to find the off leakage current. Jul 22, R1 is k and R3 is 50k.

You can not get to zero volts and you don’t need to. The photo transistor adtasheet probably an IR type can’t find a visible light onebut I expect a flash tube to emit a broad light spectrum including sufficient IR to saturate the photo transistor.

I want it to be triggered by the camera’s built in flash, but I can’t get it to work satisfactorily.


You May Also Like: Determining resistor values in a mesh. What you want to do is allow the input power source to charge up a capacitor, and then when your light sensor senses the external flash, dump that cap into the LEDs.


You route that to the base of the transistor. Resistor Values Posted by tquiva in forum: Does anyone have any suggestions? Just playing devil’s advocate here. But if your PT photo transistor is rated for 50 mS and you opt for one that is much faster, the next question is: Have I got that right? Whether that be from it’s own flash or any other light source.

Jul 21, 5. Nov 30, 18, 9, The Darlington transistor needs about 1. One-Time Programmable Memory in Action: When I shine a torch on the photo resistor, it saturates and the LEDs satasheet up bright, but when I try to activate the system with the flash, the LEDs don’t seem to work.

Jul 22, 6. Do you realize how short that flash from the camera really is? I’ve looked on-line and saw some diagrams without an R1 or an R2, but bd69 that blow the BD or the photo transistor when it saturates? Measure the current through the opto-transistor in ambient light.