Electronics-Related.com

NiMh charging formula

Started by Andy K in sci.electronics.design9 years ago 22 replies

I have a "dumb" NiMh/NiCd charger. For 9 volt batteries, it specifies 25 milliamps. The charger manual gives this charge...

I have a "dumb" NiMh/NiCd charger. For 9 volt batteries, it specifies 25 milliamps. The charger manual gives this charge formula. Charging time(h) = 1.2 x battery capacity (mAh) -------------------- charging current (mA) 13.44 hrs. Is is formula useful or is there something better that factors in the starting Voltage ? Thanks.


recommend cheap and corrosion resistant electrical contact material

Started by mike daniels in sci.electronics.design3 years ago 12 replies

I'm looking for a low cost contact material that can withstand being exposed to unconditioned warehouse conditions for months without the surfaces...

I'm looking for a low cost contact material that can withstand being exposed to unconditioned warehouse conditions for months without the surfaces becoming corroded or oxides. The shape of these will be similar to D cell batteries with a spring on one side and a flat contact on the other. The device is not a battery but mounts similarly and must work reliable on first install. No jiggling ...


OT: Can CMOS battery on PC motherboard be hot-swapped?

Started by Joerg in sci.electronics.design11 years ago 74 replies

Folks, Got a Dell Vostro 200 mini tower with XP on there that seems to be a bit off in the realtime clock lately. Around five years old so...

Folks, Got a Dell Vostro 200 mini tower with XP on there that seems to be a bit off in the realtime clock lately. Around five years old so needs a new 3V coin cell on the mobo. In order not to lose all the setup stuff, can those CR2032 coin cells be hot-swapped while the PC is running? Of course using ESD straps, being careful and all that. -- Regards, Joerg http://www.analogco...


How to stop electrical whining noise?

Started by John Doe in sci.electronics.design5 years ago 40 replies

https://youtu.be/FSwZQtqWyHw Can that whining noise be easily eliminated? I am assuming its origin is easy for some to guess. It uses...

https://youtu.be/FSwZQtqWyHw Can that whining noise be easily eliminated? I am assuming its origin is easy for some to guess. It uses brushless motors controlled by an "electronic speed control" (ESC). There is a large cap across each ESC supply plus and minus. I tried adding a 1000 ?F low ESR capacitor on the battery input but that didn't help. Thanks.


Inverters vs wallwarts

Started by bob prohaska in sci.electronics.design2 years ago 55 replies

I'm setting up a UPS for my computer/comms equipment using an inverter/charger and battery from Amazon. The equipment draw is only about 40...

I'm setting up a UPS for my computer/comms equipment using an inverter/charger and battery from Amazon. The equipment draw is only about 40 watts measured with a Kill-A-Watt, but all the associated wallwarts use capacitive-input switching power supplies. That means they only draw current at line peaks. My seat-of-the-pants guess is that the duty cycle is around 10%, meaning that the aver...


half wave rectifier

Started by TTman in sci.electronics.design8 months ago 85 replies

As part of an experiment with solar, I want to drive my 220V 3kW immersion heater with a suitable diode so that the effective power is ~1.5kW...

As part of an experiment with solar, I want to drive my 220V 3kW immersion heater with a suitable diode so that the effective power is ~1.5kW and can be driven by a smart switch so that it doesn't suck too much out of the 9.5kWh battery or solar panels.. What diode? This is UK spec. -- This email has been checked for viruses by Avast antivirus software. www.avast.com


typically stupid ED article

Started by Anonymous in sci.electronics.design4 years ago 77 replies

...

https://www.electronicdesign.com/technologies/test-measurement/whitepaper/21140081/warning-your- dmm-is-discharging-your-battery-cell?utm_source=EG+ED+Today&utm_medium=email&utm_campaign=CPS200 828010&o_eid=7322A4702401H9R&rdx.ident%5Bpull%5D=omeda%7C7322A4702401H9R&oly_enc_id=7322A4702401 H9R It's sad how bad the electronics press has become. -- John Larkin Highland Technol


EXPLAINER: 2023 tax credits for EVs will boost their appeal

Started by Fred Bloggs in sci.electronics.design1 year ago 4 replies

Last time I checked the globe is one big place. This requirement for American only manufacture is wrong. America is not the only place where...

Last time I checked the globe is one big place. This requirement for American only manufacture is wrong. America is not the only place where people require employment, and American EV industry benefits from foreign innovation, as well as vice versa. The battery minerals and materials issue could be handled by requiring the supplier country to submit to inspections and audits- which


Adapter fails to power DC motor

Started by Terry Pinnell in sci.electronics.design4 years ago 51 replies

I bought the following 4A 5V supply adapter:...

I bought the following 4A 5V supply adapter: https://cpc.farnell.com/stontronics/t6819st/ac-dc-power-supply-5v-4a-2-1mm/dp/PW04378?st=5v%20po wer%20adaptors with the aim of trying it as an alternative supply for my 16 year old curtain controller circuit. At present I successfully use 3 x AA Nimh batteries, delivering a voltage of about 3.8 to 4.1 V (measured at the battery terminals). Current


Triple Charging Gaps to Vegas

Started by Ed Lee in sci.electronics.design2 years ago 51 replies

I am bringing my Leaf to Vegas for someone to work on. Unfortunately, many mechanics refused to touch anything EV, even if only to drop the...

I am bringing my Leaf to Vegas for someone to work on. Unfortunately, many mechanics refused to touch anything EV, even if only to drop the battery down for me to work on. My Leaf currently have 15kWh, which is fine from the SF area to Bakersfield. However, there are three major charging gap in kWh. Mile gap is misleading. (1) and (3) are around 25 miles. (1) 20kWh: Baker to Valley Well R...


Running garden tools on 40-60V DC instead of 120VAC?

Started by Joerg in sci.electronics.design3 years ago 42 replies

I dread all those extension cords when using the hedge trimmer and other stuff. I found that if I connect the E-bike battery of a friend to it...

I dread all those extension cords when using the hedge trimmer and other stuff. I found that if I connect the E-bike battery of a friend to it the hedge trimmer runs somewhat slower but reliably. It had 53V DC. Those machines contain brush-type universal motors, probably with a compensation winding but not sure. Is is safe to run these with 40-60V DC over long periods of time or is ther...


Focus: Ocean shippers playing catch up to electric vehicle fire risk

Started by Fred Bloggs in sci.electronics.design7 months ago 56 replies

Another reason why import EVs are getting more expensive. Dunno how the Grimaldi shipping line even stays in business. They have procedures for...

Another reason why import EVs are getting more expensive. Dunno how the Grimaldi shipping line even stays in business. They have procedures for the loaders to disconnect the battery once it's parked in the bay, but it looks like they're not doing that. Big money involved both in very expensive load of vehicles, as well as the ship in addition to expensive maritime firefighting and r


Shady Dell laptop practices

Started by bitrex in sci.electronics.design6 years ago 41 replies

On some of the inexpensive Dell laptops they implement a hardware-lockout system intended to prevent you from using aftermarket charger bricks...

On some of the inexpensive Dell laptops they implement a hardware-lockout system intended to prevent you from using aftermarket charger bricks to charge the battery. The way they do this is there's a chip in the Dell charger that contains a unique identifier which a chip on the laptop mobo requests from it on startup over a one-wire interface. If on boot the BIOS can't confirm that the ...


Current Level Detection

Started by Cursitor Doom in sci.electronics.design3 years ago 110 replies

Gentlemen, I want to monitor current drawn from a car battery (12v lead-acid) in such a way as when it drops below 200mA, a piezzo buzzer...

Gentlemen, I want to monitor current drawn from a car battery (12v lead-acid) in such a way as when it drops below 200mA, a piezzo buzzer sounds. The range of current the monitor will see will run from 15A to around 75mA. The 15A will last for only around 10s or so and once it settles down will drop to 240mA for hours on end. This is just to monitor quiescent current drain and there will b...


CML-CML level shifter

Started by John Larkin in sci.electronics.design2 years ago 19 replies

I have a differential output from a fast CML flipflop, powered by +3 and ground, and want to drive another CML-input part. If the load gadget...

I have a differential output from a fast CML flipflop, powered by +3 and ground, and want to drive another CML-input part. If the load gadget was also powered from +3, I'd just connect them with a couple of 50 ohm traces. But the Vcc of the destination part could be anything from +3 to -2. I want full speed and DC coupling, so the ideal part to put in series with both runs is a battery ...


Sub uA battery powered current source.

Started by George Herold in sci.electronics.design6 years ago 20 replies

So I was out at UB, (picking up some stuff) I was talking with Bruce's* final grad student. He had some success biasing a resistive FIR...

So I was out at UB, (picking up some stuff) I was talking with Bruce's* final grad student. He had some success biasing a resistive FIR detector with a current source. The grey haired tech turned him onto an LM134. (A new IC for me too.) http://www.ti.com/lit/ds/symlink/lm134.pdf Apparently they are running it dry down at 1uA and either need more voltage or less current.** (Suppl...


not OT : fear

Started by John Larkin in sci.electronics.design2 years ago 143 replies

https://www.studyfinds.org/fear-for-safety-every-day/ What's wrong with kids these days? Most have been super-protected children but are...

https://www.studyfinds.org/fear-for-safety-every-day/ What's wrong with kids these days? Most have been super-protected children but are afraid of life. Engineers have to THINK, blow things up, take calculated risks. Fear warps prudent judgement. I've had interns that were afraid to touch a board powered from 5 volts, or handle a 12 volt battery. And wanted eye protection and masks ...


Low Power High Voltage Flip Flop

Started by rhor...@gmail.com in sci.electronics.design1 year ago 28 replies

I have a situation where I need to change a momentary switch to an on / off switch. This is ordinarily very easy using a JK Flip Flop, but there...

I have a situation where I need to change a momentary switch to an on / off switch. This is ordinarily very easy using a JK Flip Flop, but there is a twist. The device runs on a 6S Lithium battery, so the voltage will vary from about 18V to 25V or so. In addition, I need the power control circuit to use very little current - on the order of 100 uA - when off. It can use much mor


How do UPS trigger circuits work?

Started by bob prohaska in sci.electronics.design10 months ago 19 replies

After using a pair of inverter/charger circuits as UPS units for some months I've become curious as to how the trigger decides when to switch...

After using a pair of inverter/charger circuits as UPS units for some months I've become curious as to how the trigger decides when to switch from line power to the battery and inverter. Supposedly they trigger on wrong voltage or frequency, but they do it in less than a half-cycle, so it seems to be more than a simple relay. A cursory web search found nothing but I don't know the proper...


Need a handheld enclosure for 16x2 LCD

Started by mpm in sci.electronics.design4 years ago 15 replies

Anybody know of a good source for handheld enclosures to fit a standard 16x2 line backlit LCD display? Preferably one that also has a 9-volt...

Anybody know of a good source for handheld enclosures to fit a standard 16x2 line backlit LCD display? Preferably one that also has a 9-volt battery compartment. Plastic is preferred. (Metal is also OK) And preferably one that comes complete with a bezel. This will be for a generic (temporary-use) handheld-type tester for something that runs on an RS-485 loop. So, a place to put QTY-(1...