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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Jul 21, 7 0.


If you could build your dream bench, what would you put on it? I’d thought of this too, to protect the opto-transistor in datsheet I dialled the trim pot meter to 0ohm.

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. But if your PT photo transistor is rated for 50 mS and you opt for one that is much faster, the next question is: That’s going to be 25 mS delay in the flash of the LED’s. Lets try 30 ua in bd64 light. The unit datasheeg well, although not as bright as flash tube, but good for macro photography.

And it looks like they should work. See where I’m going with this? The light source consists of five series of ten bright white LEDs, each series with it’s own ohm resistor. When a light flash happens the opto will suddenly allow a lot more current.

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. Jul 21, 4. Discussion in ‘ General Electronics Chat ‘ started by roukeJul 21, Jul 22, 8. That’s datsaheet an SCR and a capacitor will do. R1 should only be necessary if the adjustment leg will eat too much current when the flash fires. May 27, 52 You May Also Like: Nov 30, 18, 9, I want it to be triggered by the camera’s built in flash, but I can’t get it to work satisfactorily.


The datasheet says the gain is aboutbut you seem to have a different data sheet with different gain values for different mA and volt values.

Posted by striplar in forum: Set R2 to allow that current to create not more than one volt. You route datasheeet to the base of the transistor.

Determining resistor values in a mesh. That’s not going to blow out anything. I’m working on the idea that when the built-in flash is blocked by a large macro lens at close range, the LED ring will compensate, and the camera will calculate from whatever it ‘sees’ through the lens.

BD Datasheet(PDF) – Siemens Semiconductor Group

I guess it’ll always be 3 volt, and in my case. OK, I’m going to open my mouth on this. I may be wrong – honestly, I’m not sure. No, create an account now. Yes, my password is: So I guess my main question is, how do I calculate the size of R1 and R2 so it protects both the opto-transistor and the base of the darlington at 0.


(PDF) BD649 Datasheet download

Jul 21, 5. Jul 21, 2. Resistor Values Posted by tquiva in forum: How are you darasheet mosfets? Will this work if you don’t have any way to stop the LEDs quickly? Jul 21, 1. The photo transistor darasheet probably an IR type can’t find a visible light onebut I expect a flash tube bv649 emit a broad light spectrum including sufficient IR to saturate the photo transistor.

I’m a newbie The recommended current through the LEDs is 20mA and bv649 max mA OK for a short flashhence the smaller resistors when the system is in flash mode. But yes, speed matters. Does anyone have any suggestions? Sep 24, 2, Jul 22, 9. And using the hot accessory shoe would be an option, but I like the challenge of wireless, and so far I’m not yet convinced that using the hot shoe would solve the problems I’m encountering here.

Jul 21, 3. When I shine a torch on the photo resistor, it saturates and the LEDs light up bright, but when I try to activate the system with the flash, the LEDs don’t seem to work. You can not get to zero volts and you don’t need to.

Maybe on my second try. I’m trying to make a flash slave as in the attached diagram. Do you realize how short that flash from the camera really is? But that’s something I can olny find out when the electronics work.