[sdiy] THAT 2155 on sale

[Jimmy Moore]

I'm also interested to hear about people's approach toward testing these
components -- or or the traits worth matching per application, more
generally.

On Fri, Apr 10, 2020 at 7:43 AM Oren Leavitt <obl64 at ix.netcom.com> wrote:

> I have an idea for "quick matching" photo cells.
>
> Basically one op-amp - a comparator with hysteresis (like that of a basic
> LFO)
>
> 1) Put the photo cell side in a resistor divider and connect to the
> comparator input.
>
> 2) Connect comparator output to to LED side thru appropriate current limit
> resistor.
>
> 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.
>
> An idea..
> On 4/10/20 5:52 AM, john slee wrote:
>
> Also interested in this, as I, too, have a bunch of unsorted single-cell
> vactrols. Possibly from my last (successful) Goldmine order!
>
> John
>
> On Fri, 10 Apr 2020 at 15:38, Laughing Man <laughingman647 at gmail.com>
> wrote:
>
>> 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.
>>
>> On Thu, Apr 9, 2020 at 8:18 PM Crys <crystals at sonic.net> wrote:
>>
>>> 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.
>>>
>>> crystal chris
>>> On 4/9/2020 8:22 PM, Kylee Kennedy wrote:
>>>
>>> Post came through fine.
>>> 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.
>>>
>>> Kylee
>>>
>>>
>>>
>>> On Thursday, April 9, 2020, Laughing Man <laughingman647 at gmail.com>
>>> wrote:
>>>
>>>> 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.
>>>>
>>>> On Thu, Apr 9, 2020 at 2:27 PM john slee <indigoid at oldcorollas.org>
>>>> wrote:
>>>>
>>>>> 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.
>>>>>
>>>>> 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
>>>>>
>>>>> Thanks for the heads-up, anyway.
>>>>>
>>>>> John
>>>>>
>>>>> On Fri, 10 Apr 2020 at 01:44, David G Dixon <dixon at mail.ubc.ca> wrote:
>>>>>
>>>>>> Hey SDIY Team,
>>>>>>
>>>>>>
>>>>>>
>>>>>> Electronic Goldmine has a stash of THAT 2155 VCAs on sale for $1.99
>>>>>> each, if you’re interested.
>>>>>>
>>>>>>
>>>>>>
>>>>>> Cheers,
>>>>>>
>>>>>> Dave Dixon
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