“Vishay”), disclaim any and all liability for any errors, inaccuracies or incompleteness contained in any datasheet or in any other disclosure relating to any. BPW40 | Phototransistor; λp maxnm; 32V; 20°; Lens: transparent – This product is available in Transfer Multisort Elektronik. Check out our wide range of . Part, BPW Category. Description, Silicon NPN Epitaxial Phototransistor. Company, ETC. Datasheet, Download BPW40 datasheet. Quote. Find where to buy.
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Since it is the 5RC value that is important, any values of R and C that produce 5RC in the range of say microseconds should work. If the color response is different, you might have to use a different light source. When there is no light there will be no current and Vce will be the supply voltage. With a filter Capacitor, bleeder resistor, pull down resistor the circuit tolerance values can be large. Wow – this is complicated stuff. But John Miller provides a link in his post – dating back to – for a.
Does anyone – more fluent in electronic components – know where I can buy the following I mounted the sensor in a piece of opaque plastic panel, cut to 60 by 35mm in size. The OP in that other thread I linked to ended up using K, because he needed enough sensitivity to detect the emitter when it was 10 inches away from the phototransistor.
Please do not ask for unpaid help via PM, use the forum. From a websearch, BPW is a part number for a particular phototransitor. Formal verification of safety-critical software, software development, and electronic design and prototyping.
I picked up 2 or 3 several years ago for datasheeet around with but can’t tell you much about them except they’re easy to wire up to demonstrate they’re sensitive to light. Guaranteed safe-area operation, but you have to get the wires right. The process of shutter opening and closing takes datasyeet significant amount of time in relation to the overall shutter speed, and during those periods the shutter is acting as a variable aperture – both reducing the amount of light that gets through so the effective speed is shorter than the measured speed, and also affecting the recorded diffraction and depth of field.
One poster said they had built the device using the schematic and parts list. Chris, You may well be right – I would never claim to know much about the engineering in a lens shutter – the information I quoted came from a camera repair guy who calibrated the shutter on an old Schneider S.
Thanks in bunches to you guys.
When the shutter closes, the phototransistor switches off the supply, and the capacitor discharges, producing a similar blip in the opposite direction on dayasheet trace.
I previously used a quite simple and reasonably accurate method of testing shutters in large format lenses for practical purposes, by filming the shutter opening darasheet closing using a basic mini-dv camcorder.
As you can see in the quicky picture below, they have a flatter top than the BPW The datasheet tells us here that the voltage drop is 1. Happy New Year to everyone on this group. So if a store doesn’t recognize these values, they know nothing about electronic components.
BPW40 Datasheet, PDF – Alldatasheet
Atm i’m thinking when powered up on 5V that the max forward voltage is 5V depending on the light. Your name or email address: Often in experimenters home brew circuits the component values are just something a chap had lying around.
If it’s NTSC it shoots even faster, at So let’s say i want 25mA is that good? Sorry for not attaching a reference. The spec sheet suggests you just want to obey voltage and current limits which are pretty liberal. I use a period counter for the actual measurement, but plugging the sensor into a computer soundcard would do just as well.
It is not critical – though obviously if it becomes too long then the blip will not be complete before the shutter closes, and if it is too short then it will probably be filtered out by recording circuitry.
For use, remove the lens es from the camera or shutter to be tested, and just use a domestic filament bulb, or even a small torch as the light source.
That should produce the required blips. Let’s say i want 25mA. Adding a second battery to increase the voltage may help. But, I’m moreso looking for a source of the parts rather than a revision or rehashing of the technology.
However, recording circuits are designed to handle a wide range of sound intensities, so values of R that are up to 10 times higher with values of C that are up to ten times smaller will probably also work, although the height of the blips in the trace would be less. And do the value R2 and R3 stay the same as in the first schematic? Here are some DIY alternatives: Bringing the recording into any basic DV editing software that comes for free with modern computers, allows you to literally count the number of frames the shutter is open for at a given shutter speed – so that a one second exposure should have the shutter open for 25 frames PAL or 30 frames NTSC.
That calculation looks good. So we need to choose a resistor that limits the current flow to 5mA, which would be 1kOhm. A guess is that you can probably vary the values by a few tens of percent from the exact values you have listed — configuring a phototransitor isn’t a critical application.
The purpose of R2 is to translate that current into a voltage drop that can be sensed by the Arduino. The TV lines method I linked to may give some indication of the changing effective aperture.
The last page of the datasheet shows the voltage drop for other current flows so you could use this to adjust the resistor to reduce the current flow if necessary hint: I will look at the link you give me after i posted this. You’re unlikely to get the phototransistor to draw more than a few mA even if you place to right next to the emitter. The choice of phototransistor is not very critical – most have enough response at the typical wavelength of a laser pointer to trigger the circuit, and the switching delay is quite short relative to the shutter speed typically a few microseconds.