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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So I dataasheet 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. 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. The Darlington transistor needs about 1. Mar 1, 3, 2, Jul 22, 8.

BD Datasheet, Equivalent, Cross Reference Search. Transistor Catalog

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. Jul datxsheet, OK thank you all for your thoughts on this.

That’s what an SCR and a capacitor will do. Have I got that right? But if your PT photo transistor is rated for 50 mS and you opt for one that is much faster, the next question is: Now, putting the opto-transistor right in front of be649 built-in flash? But if it’s in series with the opto-transitor, it’s multifunctional.


BD649 Datasheet, Equivalent, Cross Reference Search

Lets try 30 ua in ambient light. Jul 22, 6. Determining resistor values in a mesh. Quote of the day. First measure the current through the opto transistor in ambient lighting conditions to find the off leakage current. Will this work if you don’t have any way to stop the LEDs datasheeet R1 should only be necessary if the adjustment leg will eat too much current when the flash fires.

BD649 Datasheet

R1 is k and R3 is 50k. Solving for two resistor values in a resistor-divider network Posted by jerseyguy in forum: And it looks like they should work. LEDs and Solar Cells Combine into Devices that Emit and Absorb Light Researchers have developed double-heterojunction nanorods which can bdd649 biased to both send and receive light—in other words, a device that is both an LED and solar cell, capable of emitting and absorbing light.

So, yes I guess the IR filter might help, but the twisted pair is perhaps excessive? Whether that be from it’s own flash or any other light source.


The vd649 says the gain is aboutbut you seem to have a different data sheet with different gain values for different mA and volt values. Resistor values in flash slave Reply to Thread. Jul 22, 9. One-Time Programmable Memory in Action: 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.

Jul 23, 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.

See where I’m going with this? Jul 21, 1. Do you realize how short that flash from the camera really is? I may be wrong – honestly, I’m not sure.

I would start by re-designing this. Hypatia’s Protege likes this. You get the power in the capacitor and you can’t stop the light until the capacitor is empty. Resistor Values Posted by tquiva in forum: If you could build your dream bench, what would you put on it?