Search found 1578 matches

by dyarker
Mon May 11, 2020 8:23 pm
Forum: General Discussion
Topic: Superduper capacitor substitute for battery
Replies: 12
Views: 1158

Re: Superduper capacitor substitute for battery

Thank you! (Wonder what I pushed on the calculator???)
by dyarker
Sun May 10, 2020 9:05 pm
Forum: General Discussion
Topic: Superduper capacitor substitute for battery
Replies: 12
Views: 1158

Re: Superduper capacitor substitute for battery

It was indirect. He said he expected AAs to last 30 minutes. If it is rated 1300mAHr, that is 1.3A for 1 hour. So 2.6A for half an hour. (Though at high current loads you don't get the rated time.) A lot of LEDs, a LED headlight, or an incandescent does not matter for the question; "How much capacit...
by dyarker
Sat May 09, 2020 12:34 pm
Forum: General Discussion
Topic: Superduper capacitor substitute for battery
Replies: 12
Views: 1158

Re: Superduper capacitor substitute for battery

Just spotted a 3500F super-super-cap.

One or two of those should do too.

(a question - is this an incandescent light? because the white LEDs I've seen need 3.8V)
by dyarker
Sat May 09, 2020 12:05 pm
Forum: General Discussion
Topic: Superduper capacitor substitute for battery
Replies: 12
Views: 1158

Re: Superduper capacitor substitute for battery

Real rough. Found some nimh AAs that are 1300mAhr. So 30 minutes would 2.6A load (you won't get the rated amphours discharging them that quick) 1 RC time constant is 63% discharged. R = 2.5V / 2.6A = 0.96Ohms Time in seconds is 30min * 60S /min = 2160S T = RC so C = T/R C = 21605S / 0.96Ohms = 2250...
by dyarker
Wed May 06, 2020 8:30 pm
Forum: General Discussion
Topic: UVC Testing - Willing to pay!
Replies: 14
Views: 1646

Re: UVC Testing - Willing to pay!

Had to go looking for what the "C" in "UVC" was for. It is shorter wavelength band than UVA and UVB. I agree that anyone selling UVA or UVB for sanitizing is cheating people and giving a false sense of safety. You, and anyone helping, be careful during your experiments. Living people should not in s...
by dyarker
Sun May 03, 2020 6:41 am
Forum: General Discussion
Topic: Question about a circuit again
Replies: 4
Views: 994

Re: Question about a circuit again

A voltage divider needs at least 2 resistors. Input at top lead of upper resistor and bottom lead of lower resistor. Output to measuring circuit is junction of the 2, and bottom lead of lower resistor.

If you are only going to AC with this circuit, then you won't need the DC divider.
by dyarker
Sun May 03, 2020 12:39 am
Forum: General Discussion
Topic: Question about a circuit again
Replies: 4
Views: 994

Re: Question about a circuit again

As far as I can tell the parts to the left of the ADC are the voltage divider. (and I don't see the 1.2K you mention in the posted diagram, nor figure 7 in the linked page.) C2 and C3 may be replaced with a single 30pF. Series caps are - Ctotal = 1 / ((1/C2) + (1/C3)) (30pF is not a standard value) ...
by dyarker
Tue Apr 21, 2020 4:58 pm
Forum: General Discussion
Topic: Green wire
Replies: 4
Views: 1705

Re: Green wire

The green wire is never supposed to have current. But it is there to protect you from problems like hot coming into contact with metal case of appliance. Then it needs to be at least same size as hot to carry current to ground. Smaller could cause dangerous voltage on case. If really small it could ...
by dyarker
Wed Apr 08, 2020 11:04 am
Forum: General Discussion
Topic: Help a Fellow Out
Replies: 12
Views: 4605

Re: Help a Fellow Out

https://en.wikipedia.org/wiki/NOAA_Weather_Radio Going to need a working FM section that can be "hacked" to higher frequency than FM broadcast band. Skill level suggests $20 to $30 and trip to Best Buy (?) so he can listen to NOAA while trying to convert an old radio. (Which may not be possible if i...
by dyarker
Sun Mar 08, 2020 11:07 pm
Forum: General Discussion
Topic: laser level offset measurement
Replies: 8
Views: 3596

Re: laser level offset measurement

Shorted pair or wet junction will look like continuous "off-hook" to switch; gives busy to callers. After time will change to out of service, and gives same result as unpaid.

Cheers,
by dyarker
Sun Mar 08, 2020 12:31 am
Forum: General Discussion
Topic: Skycool
Replies: 14
Views: 3310

Re: Skycool

Oh boy, am I glad that can't really work!

((because I like to breathe))
by dyarker
Sun Mar 08, 2020 12:25 am
Forum: General Discussion
Topic: Of some interest!
Replies: 6
Views: 3343

Re: Of some interest!

!!! they closed in '06 'cuz they made machines too good to sell replacements??? (they didn't break much) :shock:
by dyarker
Sun Mar 08, 2020 12:18 am
Forum: General Discussion
Topic: fading away
Replies: 25
Views: 7432

Re: fading away

Interesting! I now have time to check 2 or 3 times a day. Of course I'm on my third retirement. :smile:
I think it will "stick" this time. (Wife now okay having me around all day :grin: )
by dyarker
Mon Feb 17, 2020 4:28 am
Forum: General Discussion
Topic: How Do you Clean A Deep Fryer?
Replies: 23
Views: 5387

Re: How Do you Clean A Deep Fryer?

" … Dihydrogen Monoxide .. a .. killer ..."

Especially breathing the liquid form.
by dyarker
Fri Jan 10, 2020 5:04 am
Forum: General Discussion
Topic: Crazy Phone issues here..
Replies: 18
Views: 7951

Re: Crazy Phone issues here..

It probably was phone cable. For longer runs from the central office I've heard of 19AWG.