Can I use a 24 V power supply to power 12 V LED strips?
Nope, you will in all likelyhood blow up the LEDs. It will try and operate in the voltage mode first and apply 24 volts to the LEDs.
How many amps does a 12v LED strip draw?
Each strip should be rated in either wattage or current at 12 volts. You need to provide this rating in order to figure out the current draw. For instance, if each strip is rated at 48 watts, then the total draw of each strip would be: 48W / 12V = 4 amps. Then, if strips are connected in parallel, the amps would be additive, so total amps would be 4 amps/strip x 4 strips = 16 amps.
In order to light an LED with a 12V supply, what resistor value is needed?
Normally, you want to minimize waste, so you connect as many LED in series as possible to consume the voltage provided, then you use a resistor to limit the current to the correct value.White LEDs are universally using 3.0 volts. You can't use 4 LEDs because there is no room for any current limitation, so we take one less ; 3 LEDs.The most popular high power white LED are 1 watt, 100 lumens, 3.0 volt, 0.333 Amps. The 3 LEDs in series need 9 volts and the resistor need to absorb the rest : 12 v - 9v : 3 volts.Using ohm law: r = v / i = 3 volt / 0.333 = 9 ohmLets use 10 ohm to make sure we don't damage the LED. The power dissipated by the resistor is: 3 volt * 0.333 a = 1 wattThis is logical since this resistor act like if we had 4 LED of 1 watt each. However, this resistor is important for protection while we exploit the full brightness available.The problem is if we connected 4 LEDs in series and no resistors, the LEDs would make almost no light at 11.9 volt but they would get destroyed at 12.1 volts. If you intend to use them in a car, the voltage is 14.4 volts when the motor run and often 11.5 volt or less when the battery is weak.Click “upvote” if you finally understood why we use resistors, downvote if i don't make sense. Close now if you don't give a f**k
Can you power 12V fans safely directly from a 24V power supply?
Well, obviously not, since you specify “directly". But a few tricks spring to mindIf they are identical, with broadly similar mechanical load (Airflow) so they want the same current, you might get away with connecting them in series. Eventually things like uneven starting will Nadger them, but you may get a year or two.When one fails you will lose them both, which is poor engineering for an essential part. Connect a high-power, heatsink mounted, Zener diode in series with each to “subtract" 12VMake a simple square wave oscillator with a 1:1 mark:space ratio. Use it to Gate on and off one or two masters. UT a reservoir capacitor across each fan, and they will see 12V.Get bone idle and use one, or two, monolithic voltage regulators to supply the fans. Plus heatsinks and capacitors.Return them for a refund and replace them with 24V fans.Throw them away and replace them with 24V fans.The one thing I would not do is try to put a resistor in series. The dissipation would be enormous, the efficiency poor, and the costs far higher than the last option..Go on, get the right ones. It will be cheaper, easier, and more reliable.
I have a power bank with 3-5 V of USB output. Can I produce 15 V of power output by connecting three open-ended USB and a light up LED strip?
No you won’t . 3–5 V is the rated voltage that is written on the power bank . It all depends on power . Considering you have unity power factor load .P=VI .Voltage is constant . like suppose 5 v rated .Now if your battery demands 10 watt power . From the above equation it will draw 2 Amp current from the system . If your charger demands 5 watt power it will draw only 1 amp current to meet the demand .Voltage is futile . It is all current that is behind everything . Voltage will be induced only if the current flows through it i.r there is a gradient and opposite charged electrons at the ends .P.S If you are not an Electrical engineer . you haven’t understood any of it .So in short No you can’t get 15 volt supply from something that has a rated (max) value of 5 volts .
Would there be any consequences by powering a 12v 0.09 ah computer fan with a 12v 7.2 ah battery? Would the fan blow up from too much current?
A2AFirst, it’s not a 0.09 AH fan. AH = Amp*Hours, which is Amps TIMES Hours, is a total energy.The fan probably says 0.09 A. This means that when 12 volts is applied it WILL DRAW 0.09 Amp. The fan determines how much current it draws. Ken L’s answer is also correct. I didn’t look at others.…The battery has 7.2 AH of total energy. 7.2 AH / 0.09 A gives 80 Hours of run time with that fully charged battery.AH/A = H [the “A”s cancel and the answer is H hours]
Can I replace the 12 V transformer of a computer’s Microlab 2.1 speakers with a 12 V battery?
Not directly. Those three wires mean that's a center-tapped transformer. You would need to supply a similar arrangements in battery, probably in the form of two 6V (two-cell) batteries with a center connection. But this poses challenges for charging - the center tap means you are likely to discharge your cell's unevenly and therefore will need a cell balancing circuit for charging. Make sure you have that capability in either the battery pack (the battery you posted might have an internal circuit) or the charger. A hobby LFP pack with cell connections for a balancer could work for exampleCenter-tapped transformer rectifier circuit in speakers look something like this to generate both positive and negative voltages for the audio components.You'd probably want to bypass the rectifier diodes when connecting the battery, but it will probably work for you to just plug in the wires exactly where the transformer used to go.