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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Without it the current through daatasheet opto-transistor at ambient light is sufficient to saturate the base of the darlington, and the LEDs are always on. But yes, speed matters. 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.

You size R3 to limit the total opto current to 0. OK, I’m going to open my mouth on this. Discussion in ‘ General Electronics Chat ‘ started by roukeBr649 21, Jul 21, 3.

You suggested a 22k in series with the trim pot meter, and none in series with the opto-transistor. Jul 22, You get the power in the capacitor and you can’t stop the light until the capacitor is empty. Jul 21, 7 0. Jul 23, Yes, my password is: 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. The darasheet source consists of five series of ten bright white LEDs, each series with eatasheet own ohm resistor.

Will this work if you don’t have any way to stop the LEDs quickly?


BD649 Datasheet, Equivalent, Cross Reference Search

One-Time Programmable Memory in Action: That’s what an SCR and a capacitor will do. Jul 21, 5. 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. Jul 21, 2. I think there should be one in series with the opto-transistor, so I can adjust the voltage at the point to the darlington to be 0v at ambient light. OK dataseet you all for your thoughts on this.

It either emits nearly invisible preflashes and analyses results to adjust flash output. Jul 22, 9.

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. Hypatia’s Protege likes dahasheet. If you could build your dream bench, what would you put on it?

But that’s something I can olny find out when the electronics work. Quote of the day. Whether that be from it’s own flash or any other light source.

Resistor Values Posted by tquiva in forum: 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. How are you with mosfets? Maybe on my second try. The Darlington transistor needs about 1. Nov 13, Lets try 30 ua in ambient light. But if it’s in series with the opto-transitor, it’s multifunctional.

Measure the current through the opto-transistor in ambient light. 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. Jul 21, 1. Mar 1, 3, 2, Set R2 to allow that current to create not more than one volt.


Just playing devil’s advocate here.


When I shine a torch on the photo resistor, it saturates dattasheet the LEDs light up bright, but when I try to activate the system with the flash, the LEDs don’t seem to work. 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. May 27, 52 You can not get to zero volts and you don’t need to.

The photo transistor is 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’ve learned quite a bit here, but I can put this project at rest and tidy up now and focus on other things again.

Resistor values in flash slave | All About Circuits

When a light flash happens the opto will suddenly allow a lot more current. See where I’m going with this? Posted by striplar in forum: Really don’t think you are going to get that circuit to respond fast enough.