Search found 1786 matches

by Externet
Thu Feb 01, 2018 8:09 am
Forum: General Discussion
Topic: Detecting a magnet... from a distance.
Replies: 23
Views: 5840

Re: Detecting a magnet... from a distance.

Hi John. I talked to the developer/inventor of that expensive chip yesterday. He suggested trying first with the $30 ones from his company, as a way to evaluate if the expensive one would justify the results/needs/cost. I ordered a 10Km coil of AWG 40 before jumping to the modern sensors; will see n...
by Externet
Wed Jan 31, 2018 5:22 pm
Forum: General Discussion
Topic: Detecting a magnet... from a distance.
Replies: 23
Views: 5840

Re: Detecting a magnet... from a distance.

Hi John. That is exactly the plan. So far.
Because ----> https://www.amazon.com/TMR9001-Ultra-hi ... ometer+tmr
:shock:

Yes, iron core can work as well as mumetal.
by Externet
Sun Jan 28, 2018 6:47 am
Forum: General Discussion
Topic: Detecting a magnet... from a distance.
Replies: 23
Views: 5840

Detecting a magnet... from a distance.

Hi. Let's raise a bit the activity here... A magnet slowly spins in the next room. Or house. Or block. Detecting its presence will depend - on the field strength of the magnet, - the sensitivity of the sensor, - the gain of the amplifier, - and perhaps something else. What method would you implement...
by Externet
Mon Jan 15, 2018 6:04 pm
Forum: General Discussion
Topic: did I blow my Amp
Replies: 6
Views: 2536

Re: did I blow my Amp

Hi. Did you connect it this way ? Being the speaker symbols actually coils of the same subwoofer ?
hak.png
You are a skilled non-beginner... Let's fix it. Power supply rails fine, right ?
Warm up the scope...
by Externet
Fri Jan 12, 2018 7:31 am
Forum: General Discussion
Topic: LOREX LW2742 Wireless Monitor........
Replies: 10
Views: 2501

Re: LOREX LW2742 Wireless Monitor........

Hi Tzap... ----> https://www.ebay.com/itm/US-Stock-10pcs-3-Pin-2-5mm-X-0-7mm-DC-Charger-Socket-Female-Jack-PCB-Power-Plug/371923366879?hash=item56985c33df:g:vUQAAOSwmCVY9We7:sc:ShippingMethodStandard!40391!US!-1 ----> https://www.alibaba.com/showroom/0.7mm-dc-jack.html ----> http://www.ebay.ca/itm/2...
by Externet
Thu Jan 04, 2018 5:53 pm
Forum: General Discussion
Topic: Nuts & Volts issues...
Replies: 2
Views: 1836

Nuts & Volts issues...

Is there a place showing the contents of the other years ?

----> http://gramlich.net/projects/nuts_and_v ... index.html

When was the first issue ? Eighty something ?
by Externet
Wed Jan 03, 2018 8:01 am
Forum: General Discussion
Topic: Very unusual desoldering method...
Replies: 9
Views: 2632

Re: Very unusual desoldering method...

Hi haklesup. The lamp bulb used on the video is a common automotive halogen 12V incandescent headlamp bulb, typically 55 to 65 Watts. One filament has a Graves shield to direct the emission towards one side (or block certain direction). There is also 120VAC halogen bulbs (without the shield) that co...
by Externet
Tue Jan 02, 2018 5:48 pm
Forum: General Discussion
Topic: Laptop charger voltage...
Replies: 1
Views: 1594

Laptop charger voltage...

At the beginning, the laptop battery packs were over 14V and the chargers about 18V-19V. Understandable. Now, some laptop packs are 11V, and still use the higher supply to charge them. Why ? Why a 12V nominal automobile 'outlet' cannot directly supply/charge a 11V laptop ? ----> https://www.amazon.c...
by Externet
Tue Jan 02, 2018 5:07 pm
Forum: General Discussion
Topic: True green 'neon' pilot bulbs...
Replies: 3
Views: 1766

True green 'neon' pilot bulbs...

Cannot find them on the market. Do you know of a source ? The ones I see now are red Ne-2 type under a green lens. One uses a powder behind the glass : ----> https://www.aliexpress.com/item/20pcs-Green-5mm-Indicator-Neon-Light-Sign-5X13mm-NeonLight-With-Resistance-for-220V-Verde-NEON-GLOW/3281119278...
by Externet
Tue Jan 02, 2018 12:52 pm
Forum: General Discussion
Topic: Very unusual desoldering method...
Replies: 9
Views: 2632

Re: Very unusual desoldering method...

A piece of sheet metal as half shroud should take care of the glare for the user. Headlamps were limited by law to 55 Watts, but that was a looong ago.
by Externet
Sun Dec 31, 2017 6:58 pm
Forum: General Discussion
Topic: Very unusual desoldering method...
Replies: 9
Views: 2632

Very unusual desoldering method...

:grin: Hi fellows. Have to share this; worth trying. Come back with your observations, results, comments, adaptations, improvements. Am sorry it has some advertisements embedded... Get your finest tweezers ready, it is a very nice way to harvest valuable parts from discarded equipment, enjoy : :idea...
by Externet
Wed Dec 13, 2017 3:39 pm
Forum: Up For Grabs
Topic: Wanted : electret condenser microphone capsules...
Replies: 10
Views: 2674

Re: Wanted : electret condenser microphone capsules...

Electrets arrived from China last week. As expected, not vented, another idiot vendor and the typical ignorant advertising.
Am drilling the ones I have for the project. Done. Erase the blackboard...
by Externet
Sun Dec 03, 2017 6:22 am
Forum: General Discussion
Topic: unmarked transformer
Replies: 8
Views: 2175

Re: unmarked transformer

Very unlikely the blues are related to the reds. Prove by probing for continuity between them. They should not.
The blues should provide power for yielding 5VDC circuitry, the center-tapped 12-0-12 for around 24VDC. Any can be used alone, leave the other disconnected if not needed.
by Externet
Sat Dec 02, 2017 5:47 am
Forum: General Discussion
Topic: unmarked transformer
Replies: 8
Views: 2175

Re: unmarked transformer

Measure the voltage at the blue wires the same way you did finding 12-0-12 at the reds. If there is voltage, is another secondary winding for other voltage uses. If no voltage; unplug and measure resistance. If zero ohms, it could be a thermal fuse. If open, may be an open thermal fuse. A transforme...
by Externet
Mon Nov 20, 2017 11:34 am
Forum: Up For Grabs
Topic: Wanted : electret condenser microphone capsules...
Replies: 10
Views: 2674

Re: Wanted : electret condenser microphone capsules...

Do not care about directionality, but the noise cancelling feature does not bother to have.
Building scuba intercoms and pressure at depth would burst the electret film if not vented...