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18v C cell?

Started by Tabby in sci.electronics.design3 years ago 11 replies

Is there an 18v battery about the size of a C cell? A zener tester, probably 1970s, that goes upto 17v max, takes what looks like a single C cell....

Is there an 18v battery about the size of a C cell? A zener tester, probably 1970s, that goes upto 17v max, takes what looks like a single C cell. There is no circuitry that could up the v as far as I can tell.


Word for connecting something nicely without voltage fluctuation?

Started by Commander Kinsey in sci.electronics.design1 year ago 27 replies

I asked this before, but I think on alt.usage.english, and never found a word for it. Say you connect a device to a battery, and in doing so,...

I asked this before, but I think on alt.usage.english, and never found a word for it. Say you connect a device to a battery, and in doing so, the connection goes on then off then on then then off because of a bad connection while you're tightening it. What word would describe that?


smartphones app as fever thermometer

Started by Jan Panteltje in sci.electronics.design9 months ago

An app can transform smartphones into thermometers that accurately detect fevers ...

An app can transform smartphones into thermometers that accurately detect fevers https://www.sciencedaily.com/releases/2023/06/230621164649.htm No extra hardware needed, uses smartphone battery temperature sensor.


Simple audio amp design

Started by Cursitor Doom in sci.electronics.design2 years ago 93 replies

Greetings, gentlemen, I have a vintage MW/LW/SW 12V battery-powered radio I picked up recently at a yard sale. Being 50 years old, however,...

Greetings, gentlemen, I have a vintage MW/LW/SW 12V battery-powered radio I picked up recently at a yard sale. Being 50 years old, however, it has a few faults and needs realignment and whatnot. Before I can proceed with that, I've discovered that the transistors it uses (mostly obsolete germanium devices) suffer from tin whiskers so I will need to re-jig the board so they can be repl...


inverter

Started by Jon in sci.electronics.design12 years ago 3 replies

Here's my inverter for power outages: http://jons-math.bravehost.com/inverter.html I've got it on a shelf to clamp on to my truck battery. ...

Here's my inverter for power outages: http://jons-math.bravehost.com/inverter.html I've got it on a shelf to clamp on to my truck battery. Then I'm running an extension cord through the wall of my trailer, turn the circuit breaker off and plug into the circuit.


150W Stirling Engine?

Started by Ed Lee in sci.electronics.design11 months ago 30 replies

I want to try this emergency battery charger: https://www.ebay.com/itm/185836877680 150W output? Or do they mean 150W LED bulb? Perhaps...

I want to try this emergency battery charger: https://www.ebay.com/itm/185836877680 150W output? Or do they mean 150W LED bulb? Perhaps 10W real output? What's the benefit of twin cylinders vs. the single cylinder version?


Why would anyone buy an e-reader?

Started by Fred Bloggs in sci.electronics.design2 years ago 18 replies

Like Amazon Kindle reader? Unless you have really sensitive eyes, read all the time and need that anti-glare feature. They seem to lack internet...

Like Amazon Kindle reader? Unless you have really sensitive eyes, read all the time and need that anti-glare feature. They seem to lack internet connectivity, such as allowing a google search of something in the text as you're reading, which I take to be a real limitation. Battery longevity feature is nice but who really needs it.


Low coefficient NTC resistors?

Started by Sylvia Else in sci.electronics.design2 years ago 42 replies

Anyone aware of such a thing? Clearly, one can achieve that just by putting a thermistor in series with an ordinary resistor, but my UPS...

Anyone aware of such a thing? Clearly, one can achieve that just by putting a thermistor in series with an ordinary resistor, but my UPS seems to contain a single component that behaves that way - perhaps less than 1% at 20 Celcius - it's in the circuit that controls the battery charging float voltage. Did they perhaps exist 20 years ago (when my UPS was made), for some reason? Sylv...


Carbon Pile

Started by OldGuy in sci.electronics.design10 years ago 12 replies

Who makes a good stable carbon pile? Stable as in it maintains its resistance as current is varied. 200 amp range, 100 VDC. Currently using a...

Who makes a good stable carbon pile? Stable as in it maintains its resistance as current is varied. 200 amp range, 100 VDC. Currently using a battery load tester but I want something I can mount on my own equipment. e.g. I have DC motor that I want to voltage up to see how it draws.


Is 3 Watts really too much to ask?

Started by Cursitor Doom in sci.electronics.design2 years ago 53 replies

Gentlemen, in pursuance of what is turning out to be a jinxed project (installing a dashcam) I'm attempting to drop 14.5V (the normal battery...

Gentlemen, in pursuance of what is turning out to be a jinxed project (installing a dashcam) I'm attempting to drop 14.5V (the normal battery voltage whilst the engine is running) to 5V for the camera. The camera draws at most 300mA so the regulator (an L7805CV) shouldn't find that task too much of a struggle, since it only has to disspate just under 3 Watts by my reckoning. I'd have ...


OT: Lead Acid Float Charger

Started by Jim Thompson in sci.electronics.design8 years ago 79 replies

I drive my pick-em-up truck every few months. So the battery is dead when I go to use it... like today :-( I'm looking for recommendations...

I drive my pick-em-up truck every few months. So the battery is dead when I go to use it... like today :-( I'm looking for recommendations for the _best_ (*) float charger I can buy to just plug the truck into when it's parked. (*) Cost no object. ...Jim Thompson -- | James E.Thompson | mens | | Analo...


Any low power low frequency quadrature receivers?

Started by Joerg in sci.electronics.design11 years ago 56 replies

While looking at a single sideband receiver project that may be coming up I checked the usual suspects for quadrature demodulators. Many...

While looking at a single sideband receiver project that may be coming up I checked the usual suspects for quadrature demodulators. Many won't (technically ...) go much below 100MHz. Some do and I need to be more in the 5-10MHz region. But they are massive guzzlers when it comes to draining the battery. Like this one which slurps a whole watt (!): http://cds.linear.com/docs/Datasheet/5584f....


Lead Acid puzzle

Started by Tabby in sci.electronics.design4 years ago 34 replies

Cart with 2x 12v 33Ah progolf AGM lead acids. 1.5 years after fitting new batteries the available range is down to below 10%. I'm not clear what's...

Cart with 2x 12v 33Ah progolf AGM lead acids. 1.5 years after fitting new batteries the available range is down to below 10%. I'm not clear what's gone wrong. The charger in use has been a cheap chinese one with 2x13.7v=27.4v output. Single stage charging only. It has always been promptly charged after use, and never run below 50% charge. I checked the battery voltages after charge, they wer...


oops

Started by Jan Panteltje in sci.electronics.design1 year ago

https://arstechnica.com/information-technology/2022/11/researchers-break-security-guarantees-of- tte-networking-used-in-spacecraft/ And will...

https://arstechnica.com/information-technology/2022/11/researchers-break-security-guarantees-of- tte-networking-used-in-spacecraft/ And will SLS even fly or just explode or crash? It Has To Fail! It almost has to fail, 16 years of development... Bad solder joints, burned out LM317, dead backup battery after 16 years... rotten electrolytics.. rust!


Li-ion UPS battery substitution in UPS

Started by Bert Hickman in sci.electronics.design1 year ago 72 replies

Does anyone have any experience swapping out old lead-acid batteries for Li-ion equivalents in a UPS? I see these batteries advertised as...

Does anyone have any experience swapping out old lead-acid batteries for Li-ion equivalents in a UPS? I see these batteries advertised as replacements, but I'm concerned about their safety in this application. New Li-ion UPS systems seem to be extremely expensive.


How about it? Experiments of the third kind , take 999999.

Started by Jan Panteltje in sci.electronics.design12 years ago 59 replies

This is an idea for an experiment I may or may not do. The background: There have been reported seasonal variations in radioactive decay in the...

This is an idea for an experiment I may or may not do. The background: There have been reported seasonal variations in radioactive decay in the past. Now If I took a simple tritium light, and a good quality photo-diode, put both in a light proof box, and logged that with a 10 bit PIC ADC with a decent Vref for say a year to FLASH, say 1 sample / hour, run the whole thing of some battery. ...


TL431 replacement with 1.2V reference???

Started by mike in sci.electronics.design9 years ago 24 replies

I need an MP3 player that runs 24/7. All the ones I have shut down and switch to file transfer mode when you plug in USB. So, I think I need a...

I need an MP3 player that runs 24/7. All the ones I have shut down and switch to file transfer mode when you plug in USB. So, I think I need a 1.5V AAA battery eliminator. All my wall warts use a TL431 as regulator. If I could find a replacement with 1.2V-ish reference in TO-92 I could just drop it in and change one resistor to get 1.5V. What's a good cheap, shunt-regulator IC that wi...


poking rs232 port BMS

Started by legg in sci.electronics.design4 years ago 13 replies

I've got a battery management unit that is reluctant to demonstrate functionality. The vendor's terminal com software seems non-functional...

I've got a battery management unit that is reluctant to demonstrate functionality. The vendor's terminal com software seems non-functional (will not install). So far the only evidence of life is a control line (one of three) hard on, and rare /XFFE /FFF signalled outputs on the rs232 port. Internal DC-DC fails to power LEM sensor. Balancing terminals seem inactive. Can anyone recom...


Tesla Semi completes 500-mile journey weighing in at 81,000 pounds

Started by Fred Bloggs in sci.electronics.design1 year ago 98 replies

These monsters have a 1,000 kWh battery pack. Of course they're not going to tell you it was doing only 25 MPH all the...

These monsters have a 1,000 kWh battery pack. Of course they're not going to tell you it was doing only 25 MPH all the way... https://www.teslarati.com/tesla-semi-81k-pounds-500-miles-range-elon-musk/