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.
Yes, my password is: You size R3 to limit the total opto nd649 to 0. First measure the current through the opto transistor in ambient lighting conditions to find the off leakage current.
Quote of the day. But that’s something I can olny find out when the electronics work. Now, putting the opto-transistor right dztasheet front of the built-in flash? I’m trying to make a flash slave as in the attached diagram. Jul 22, 7.
R1 is k and R3 is 50k. Bbd649 if your PT photo transistor is rated for 50 mS and you opt for one that is much faster, the next question is: And it looks like they should work. When a light flash happens the opto will suddenly allow a lot more current.
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. OK thank you all for your thoughts on this.
Generally a good job for an SCR. Will this work if you don’t have any way to stop the LEDs quickly? That’s what an SCR and a capacitor will do.
Jul db649, 5. Discussion in ‘ General Electronics Chat ‘ started by roukeJul 21, The opto-transistor can only allow. Determining resistor values in a mesh. Your name or email address: Does anyone have any suggestions?
So, yes I guess the IR filter might help, but the twisted pair is perhaps excessive? Jul 21, 1.
BD Datasheet – General purpose NPN Darlington transistor from Power Innovations
And the tailing off from the phosphorous in the white LEDs may become a problem at fast moving objects. 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.
You can not get to zero volts and you don’t need to. Nov 30, 18, 9, But yes, speed matters. Jul 21, 4. If you could build your dream bench, what would you put on it?
You suggested a 22k in series with the trim pot meter, and none in series with the opto-transistor. I would start by re-designing this. Measure the current through the opto-transistor in datashheet light.
See where I’m going with this? R1 should only be necessary if the adjustment leg will eat too much current when the flash fires. I’d thought of this too, to protect the opto-transistor in case I dialled the trim pot meter to 0ohm. Sep 24, 2, I guess it’ll always be 3 volt, and in my case. Posted by striplar in forum: Lets try 30 ua in ambient light.
Jul 22, 6. Hypatia’s Protege likes this. The datasheet says br649 gain is aboutbut you seem to have a different data sheet with different gain values datasheey different mA and volt values. But if it’s in series with the opto-transitor, it’s multifunctional. That’s not going to blow out anything. 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.
The light source consists of five series of ten bright white LEDs, each series with it’s dataeheet ohm resistor. I’ve looked on-line and saw some diagrams without an R1 or an R2, but wouldn’t that blow the BD or the photo transistor when it saturates?
May 27, 52 Really don’t think you are going to get that circuit to respond fast enough. Jul 22, 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.