“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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Let’s say i want 25mA. And about the emitter and the collector, datasheeet the image there is a small square with a capital A in it, i first thought it was a indication for Anode, is that wrong?

But John Miller provides a link in his post – dating back to – for a. 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 and closing using a basic mini-dv camcorder. It then gave the current through the device. The purpose of R2 is to translate that current into a voltage drop that can be sensed by the Arduino.

Shutter Speed Tester – DIY Build – Electronics Parts

I suggest checking the yellow pages or the web for a store near you that actually sells electronic components. Saying that you want a pF capacitor and a Ohm resistor is like saying that you want a hpw40.

The value of R should not be decreased significantly, since that could lead to the vpw40 being effectively short circuited – if in doubt, choose a higher value for R. I will look at the link you give me after i posted this. When these homebrew schematic are published one may find oneself placing resistors or caps in parallel to meet some value that really doesnt matter, or radically does matter. With a filter Capacitor, bleeder resistor, pull down resistor the circuit tolerance values can be large.

Does anyone – more fluent in electronic components – know where I can buy the following A single phototransitor should be cheap, so you won’t be out much if it doesn’t work.


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 datashest 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. Note this is super simplified to a first approximation only but it will do to work with.

Adding a second battery to increase the voltage may dataeheet. Sorry for not attaching a reference. Use or pF, it doesn’t have to be too accurate for this application. Also i don’t see a voltage drop, is that because it depends on the amount of light it is receiving? That calculation looks good. Now, exactly Ohms isn’t a standard value. Ok, so mA is too much current for those things.

Or do we assume the current is fixed at 5mA and try to ensure the voltage drop across the phototransistor is correct to toggle the reading at the collector? Bought a calumet tester couldn’t be happier. In timing like a RC circuit the tolerances of R and C matter. This is probably the problem encountered by the previous poster.

Dwtasheet a link to the items in the online catalogue: The former is assured by the power source you use, whereas the latter is typically done with a resistor.

I’d really like to hear some more about the phototransistor. If you have to order by mail, the shipping cost will be larger than the cost of these items. John suggested that the design is flexible about what phototransitor is used, so if you can’t find a BPW or BPW, just try what you can find.

So if a store doesn’t recognize these values, they know nothing about electronic components. It relies on the phototransistor having a fast switching speed in response to seeing the light through the shutter.

See this thread http: And do the value R2 and R3 stay the same as in the first schematic? The main problem is getting the risetime of the sensor down, and in the end I chose a readymade light-sensitve switch IC, rather than use discrete components, because it had a satasheet reaction time.


Wow – this is complicated stuff. About the detector, the wpb40 that one is next. I bought all the crap put one together didn’t work fussed with it.

Shutter Speed Tester – DIY Build – Electronics Parts | Photography Forums

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. Often in experimenters home brew circuits the component values are just something a chap had lying around. Now that the holiday ‘rush’ is over, I’ll make some phone calls to electronics outlets.

I built a homemade shuttertester some time ago. So what do i need? Happy New Year to everyone on this group. Guaranteed safe-area operation, but you have to get the wires right. It always takes longer than you expect, even when you take into account Hofstadter’s Law. If it’s PAL it shoots at 25 frames a second, has time code, and is pretty accurate by design. One poster said they had built the device using the schematic and parts list.

BPW40 Datasheet PDF

Nevertheless my tests suported the repair guy’s assertion. The sensor output goes to the pulse counter through cheap screened figure-of-eight audio cable. The phototransistor will draw an amount of current depending on how much light it senses.

As you can see in the quicky picture below, they have a flatter top than the BPW If it’s NTSC it shoots even faster, at Maybe at faster speeds a different spring is active.