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<p>I have an idea for "quick matching" photo cells.</p>
<p>Basically one op-amp - a comparator with hysteresis (like that of
a basic LFO)</p>
<p>1) Put the photo cell side in a resistor divider and connect to
the comparator input.</p>
<p>2) Connect comparator output to to LED side thru appropriate
current limit resistor.</p>
<p>The circuit should self oscillate at an amplitude/frequency
determined by the LDR's light/dark resistance and lag time
characteristics. Plug different photocells into same circuit and
sort them by matches in amplitude/frequency shown on oscilloscope.</p>
<p>An idea..<br>
</p>
<div class="moz-cite-prefix">On 4/10/20 5:52 AM, john slee wrote:<br>
</div>
<blockquote type="cite"
cite="mid:CAK+JDy2pXZbMJxB6QWjcUcBD7D1FE0JJ3CN9QiEsCgu9GL16ng@mail.gmail.com">
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<div dir="ltr">
<div>Also interested in this, as I, too, have a bunch of
unsorted single-cell vactrols. Possibly from my last
(successful) Goldmine order!</div>
<div><br>
</div>
<div>John<br>
</div>
</div>
<br>
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">On Fri, 10 Apr 2020 at 15:38,
Laughing Man <<a href="mailto:laughingman647@gmail.com"
moz-do-not-send="true">laughingman647@gmail.com</a>>
wrote:<br>
</div>
<blockquote class="gmail_quote" style="margin:0px 0px 0px
0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<div dir="ltr">
<div>This might be off topic, but I've been trying to test
photocells myself recently in order to make up some
vactrols for a 208. What kind of circuit would you use to
test to the spec of the datasheet? Putting 10mA through a
resistance of 1 megohm produces a ridiculous voltage drop,
so I'm not sure how I'm supposed to 'bias' the photocell
so I can test if it's response matches the datasheet.</div>
</div>
<br>
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">On Thu, Apr 9, 2020 at
8:18 PM Crys <<a href="mailto:crystals@sonic.net"
target="_blank" moz-do-not-send="true">crystals@sonic.net</a>>
wrote:<br>
</div>
<blockquote class="gmail_quote" style="margin:0px 0px 0px
0.8ex;border-left:1px solid
rgb(204,204,204);padding-left:1ex">
<div>
<p>yeah, me too. i got quite a few hundred, then i
bought a box of envelopes and tested out a big pile of
them and made envelopes full of matching units.</p>
<p>crystal chris<br>
</p>
<div>On 4/9/2020 8:22 PM, Kylee Kennedy wrote:<br>
</div>
<blockquote type="cite">Post came through fine.
<div>Interesting I'll have to find that Vactrol.
Electronic Goldmine is well know for selling out of
spec Vactrols in the past. A lot of the stuff here
is surplus from manufacturers that's why they can
sell them so cheaply. I still have a few hundred
dual leg Vactrols from their blow out sales...All
with different responses.</div>
<div><br>
</div>
<div>Kylee</div>
<div><br>
</div>
<div><br>
<br>
On Thursday, April 9, 2020, Laughing Man <<a
href="mailto:laughingman647@gmail.com"
target="_blank" moz-do-not-send="true">laughingman647@gmail.com</a>>
wrote:<br>
<blockquote class="gmail_quote">
<div dir="ltr">First time posting, so I'm not sure
if I'm sending this out right, but I also
stumbled across a 3-lead photocell on their site
as well. Sounds like an easy way to make some
home-baked 5c3/2's.<br>
</div>
<br>
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">On Thu, Apr 9,
2020 at 2:27 PM john slee <<a
href="mailto:indigoid@oldcorollas.org"
target="_blank" moz-do-not-send="true">indigoid@oldcorollas.org</a>>
wrote:<br>
</div>
<blockquote class="gmail_quote">
<div dir="ltr">
<div>Interesting. I tried to order some.
Unfortunately their payment processor is
rejecting my cards due to (incorrectly)
failing AVS checks, and they inexplicably
don't allow Paypal for Australia.
Infuriating.</div>
<div><br>
</div>
<div>They need to bring their site forward
at least 20 years. Limiting people to
10-character passwords is awful (see: NIST
guidelines) and also while I don't have
proof of this, based on the way their form
flow works, I suspect they're being very
naughty and storing credit card CVV info.
This is absolutely not allowed<br>
</div>
<div><br>
</div>
<div>Thanks for the heads-up, anyway.<br>
</div>
<div><br>
</div>
<div>John</div>
</div>
<br>
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">On Fri, 10
Apr 2020 at 01:44, David G Dixon <<a
href="mailto:dixon@mail.ubc.ca"
target="_blank" moz-do-not-send="true">dixon@mail.ubc.ca</a>>
wrote:<br>
</div>
<blockquote class="gmail_quote">
<div lang="EN-US">
<div>
<p class="MsoNormal"><span>Hey SDIY
Team,</span></p>
<p class="MsoNormal"><span> </span></p>
<p class="MsoNormal"><span>Electronic
Goldmine has a stash of THAT 2155
VCAs on sale for $1.99 each, if
you’re interested.</span></p>
<p class="MsoNormal"><span> </span></p>
<p class="MsoNormal"><span>Cheers,</span></p>
<p class="MsoNormal"><span>Dave Dixon</span></p>
</div>
</div>
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