Can anyone explain how this battery charger works?

Started by Commander Kinsey in sci.electronics.basics8 months ago 62 replies

https://imgur.com/a/b8l5qKQ Look at the circuit diagram. The positive of the battery is only connected through a capacitor. How can a...

https://imgur.com/a/b8l5qKQ Look at the circuit diagram. The positive of the battery is only connected through a capacitor. How can a capacitor possibly pass DC current to allow the battery to charge?


So, how DO I charge a 6V SLA battery?

Started by Anonymous in sci.electronics.basics15 years ago 26 replies

I bought a 6V, 6Ah battery from Home Depot to power my 3-year-old's toy electric car (the kind that a kid can ride). The previous...

I bought a 6V, 6Ah battery from Home Depot to power my 3-year-old's toy electric car (the kind that a kid can ride). The previous battery didn't hold a charge when I bought the car. One reference from batteryuniversity.com mentioned something about 2.50V per cell for SLA batteries. I'm assuming my battery has 3 cells. Another website mentions use of an L200 voltage regulating chip (http...


75332P MOSFET drain connected to which battery terminal?

Started by John Doe in sci.electronics.basics11 years ago 11 replies

I have a 75332P MOSFET on a cordless drill controller heatsink. I guess it's part of a pulse width modulator. The drain (flange) connects...

I have a 75332P MOSFET on a cordless drill controller heatsink. I guess it's part of a pulse width modulator. The drain (flange) connects directly to one of the battery terminals. Does the MOSFET drain go directly to the battery minus/ground terminal? Or does it go to the battery plus terminal? Thanks. -- My application... I'm desperately trying to develop a better inline ...


Jus Run the Voltage Backwars Thru a 8 v Battery

Started by Bret Cahill in sci.electronics.basics6 months ago 1 reply

The Fieri light runs on 4 rechargeable cells 2p X 2s. Just wire it so that the voltmeter always gets 8 volts less than the ebike battery.

The Fieri light runs on 4 rechargeable cells 2p X 2s. Just wire it so that the voltmeter always gets 8 volts less than the ebike battery.


Overcharging NiMh batteries?

Started by Bill Bowden in sci.electronics.basics7 years ago 3 replies

My neighbor has a solar powered outdoor decoration light that cycles through several colors but only runs for maybe an hour at night. It has a...

My neighbor has a solar powered outdoor decoration light that cycles through several colors but only runs for maybe an hour at night. It has a single 1200 mAh 1.2 volt rechargeable battery and a couple small solar cells to charge the battery. I measured the load current at 15 milliamps and the charge current at only 1.3 milliamps so it appears the solar array is not charging the battery ...


Are there 22.5v. batteries?

Started by Ramon F. Herrera in sci.electronics.basics11 years ago 38 replies

I was looking at the schematics of the first transistor radio, the Regency TR-1, and noticed that it uses a 22.5v....

I was looking at the schematics of the first transistor radio, the Regency TR-1, and noticed that it uses a 22.5v. battery. http://people.msoe.edu/~reyer/regency/schematic.jpg Later models use a more normal battery such as 9v. -Ramon


Replacement for Li-Ion battery

Started by AK in sci.electronics.basics2 months ago 2 replies

I want to replace this 3.7 Volt Lithium Ion battery. The dimensions are 1 14/16 x 8/16 inch. Can some help me find a...

I want to replace this 3.7 Volt Lithium Ion battery. The dimensions are 1 14/16 x 8/16 inch. Can some help me find a replacement? Thanks, Andy https://imgur.com/a/w5v2dHI


DC 17V from PC power supply?

Started by Mr. Man-wai Chang in sci.electronics.basics9 years ago 22 replies

1. If I shorted the +5V and +12V in the molex connector, would I get +17V? What's the max. current? 2. Could I use 17V to charge a...

1. If I shorted the +5V and +12V in the molex connector, would I get +17V? What's the max. current? 2. Could I use 17V to charge a notebook battery rated 16V and 3.8A? Would it hurt the battery? -- @~@ Remain silent. Nothing from soldiers and magicians is real! / v \ Simplicity is Beauty! May the Force and farces be with you! /( _ )\ (Fedora 18 i686) Linux 3.9.6-200....


How long to charge 9v nimh battery

Started by AK in sci.electronics.basics9 months ago 4 replies

I have a 9V 180 ma discharged Nimh battery that I am charging at 25ma. How long will it take to charge? Thanks, Andy

I have a 9V 180 ma discharged Nimh battery that I am charging at 25ma. How long will it take to charge? Thanks, Andy


*small* spark generator

Started by ScottM in sci.electronics.basics10 years ago 20 replies

I need to generate sparks between two pieces of brass, about a half inch apart or slightly more. I want each spark to be triggered by a logic...

I need to generate sparks between two pieces of brass, about a half inch apart or slightly more. I want each spark to be triggered by a logic line going high (going low would work, too.) The voltage supply is 6v or 12v from a battery. The problem is that I need the circuit to fit inside a 1.5" inside diameter PVC pipe, and not take up more than, say, 3" of the pipe length, discounting battery...


Power Routing Switch

Started by Rick C in sci.electronics.basics2 years ago 1 reply

Working on a gadget that uses a 12 volt motor (10 amp peak) and misc electr= onics running on lower voltages. It is powered from an external PSU...

Working on a gadget that uses a 12 volt motor (10 amp peak) and misc electr= onics running on lower voltages. It is powered from an external PSU like a= laptop supply, but 12 volts. There is also a sealed lead acid battery for= backup when the power fails. =20 This design uses pairs of pFETs to route the power from the 12 volts input = when present, or the battery when the line is not p...


EVs Will Soon Be Vastly Cheaper To Own Than Carbon Fuel Vehicles

Started by Bret Cahill in sci.electronics.basics2 years ago 35 replies

Daimler and others already pointed out that the battery upon which Tesla's e-Semi is based does not exist. Tesla isn't just hoping a better...

Daimler and others already pointed out that the battery upon which Tesla's e-Semi is based does not exist. Tesla isn't just hoping a better battery will appear, however. They have good information on it and it isn't all that insider: http://www.businessinsider.com/new-discovery-could-be-death-blow-to-traditional-lithium-ion-batt eries-2017-12 https://www.theguardian.com/environment/2017/dec


Calculate run time of battery to a specified voltage

Started by AK in sci.electronics.basics3 years ago 11 replies

I want to calculate approx run time of a D cell with a capacity of 13,000 Mah. I assume that Time(H) = Capacity(Ah)/Current(A) equals a final...

I want to calculate approx run time of a D cell with a capacity of 13,000 Mah. I assume that Time(H) = Capacity(Ah)/Current(A) equals a final battery voltage of 0 volts which will not work in my case. I need a calculation for an ending voltage of around 2.0 volts. (At 2.0 volts, my clock starts losing time.) Thanks


Solar charger

Started by AK in sci.electronics.basics1 year ago 10 replies

I have a solar charging I am using with my car battery. The current voltage of the battery is 12.7 volts. And the charger is still...

I have a solar charging I am using with my car battery. The current voltage of the battery is 12.7 volts. And the charger is still charging. Here are some specs for the charger. Rated power output = 5W Operating power voltage = 18V Operating power current = .33A Trickle charging current = .2A Floating charging Voltage = 13.8 Overcharge Protection Voltage = 14.1 Voltage At what ...


Roof co-ax amp supply question

Started by Charlie+ in sci.electronics.basics3 years ago 2 replies

Hi All, I want to test out an in-line aerial amp and have supplied it with 12V battery and circuit for testing as below glummed from the web...

Hi All, I want to test out an in-line aerial amp and have supplied it with 12V battery and circuit for testing as below glummed from the web and spares. I can build things but am no shakes on real theory. It works well but seems a bit noisy (hiss on stereo) but I have it down at the RX end of the co-ax at the moment prior to going up the roof with it, so that might make quite a difference t...


Failure mode of LEDs in overcurrent situation

Started by Andrew T. in sci.electronics.basics3 years ago 3 replies

I'm curious about what happens to an LED when it is exposed to a moderate overcurrent situation. This question came about as I was...

I'm curious about what happens to an LED when it is exposed to a moderate overcurrent situation. This question came about as I was troubleshooting some small white LED lights I built using 3 5mm LEDs and a current limiting resistor to run on 12Vdc (supplied by a lead-acid battery charged by solar). After some time, many of these strings would start to flicker or blink. I was about to po...


Solar Charging Night Light not working

Started by Alberto in sci.electronics.basics2 years ago 24 replies

Hi all, I am trying to implement a very simple solar charged night garden light. Schematics is here:...

Hi all, I am trying to implement a very simple solar charged night garden light. Schematics is here: https://www.jameco.com/Jameco/workshop/JamecoFavorites/solarled.html Basically a solar panel charges a battery. When the solar panel output is low (at night), a joule thief circuit lights a led. The joule thief part works just fine, the problem is that the dark detector (2n3906 + 4.7K resis...