A novel shutter tester

["Paul A. Lehman" <palehman@xxxxxxxxxxxxx>]

This came through the camera collecters (IDCC) group,
thought it may prove useful to this group also.
Paul A. Lehman


 http://www.geocities.com/Yosemite/2131/shspeed.html
> 
> i just ran into this site recently and though others may be interested
> in seeing it. here you can find explanations and detail about building
> a shutter testing device for about 5 bucks
> 
> andre
> 

> That circuit could come in handy.  What's clever is the use
> of a computer sound card as an oscilloscope.  I never would
> have thought of that.
> 
> For those without Web access, here's the circuit.
> Connect the following items in a series loop.
> The order doesn't matter as long as battery + goes
> to the collector.
> 
>    1.5V battery (+ connects to collector of phototransistor below)
>    BPW 40 photo transistor
>    5k ohm resistor
>    on/off switch
>    male submin jack to plug into "Mic In" on sound card
> 
>    Fire shutter to let light onto phototransistor, and
>    record the resulting "sound" with your sound card.
>    Edit with CoolEdit 96 to look at timing of waveform.
>  mark