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29 views

Finding the current through resistor in source free parallel RLC Circuit for t>0

My solution: Since alpha >w0, so response is overdamped. Current through inductor:$$ Il(0-)=Il(0+)=6 $$Voltage across capacitor: $$Vc(0-)=Vc(0+)=0V$$ Current through resistor: $$ Ir(t)=A1e^{s1t} + ...
0
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1answer
55 views

why add a resistor parallel to voltage source? [duplicate]

Sometimes I see a resistor parallel to voltage source (such as image below), isn't it completely useless ? Edit: I see the other similar question now, but I think it doesn't have the right keyword ...
0
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4answers
105 views

Large parallel strings of LEDs

I want to drive multiple strings of XTE LEDs (total of ~36 LEDs). The relevent (-ish) specs are as follows: I_f,max = 1.5 A Desired I_f = 0.5 A V_f = 2.94 V (0.5A @ 85C) According to some ...
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1answer
43 views

Multiple DC Voltage sources in parallel

I'm building an alarm system (paradox EVO192 with ZX8 extension modules) and was hoping to have separate sections of the system each powered by it's own battery backed up power supply (something like ...
3
votes
2answers
44 views

Parallel input to serial output

I have been learning a bit about electronics. In particular I have been playing with the shift register 74HC595. Here I understand how bits are moved into the register serially, that is one bit at the ...
0
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2answers
57 views

What is the difference between charging batteries in series and parallel?

For example, if I have a charger that supplies 300 milliamps: Will it take a bit more than 3 hours to charge a 900 mAh AA battery? What if I have 4 AA batteries in series? Will it still take 3 ...
12
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3answers
282 views

How many MOSFETs can we safely parallel in condition of very high currents? I had problems with a motor application at 48V 1600A

I tried with some configurations in which 16+16 MOSfets of 240A each (really they are case limited to 80-90A because of source terminal, but i doubled this termminal with a very thick copper wire for ...
0
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1answer
18 views

AC voltage regulator in parallel

I have two voltage regulator which works on ac. They are both the same model and provide a maximum power of 3000w. I would like to plug their outputs together to make a 6000w total voltage regulator. ...
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4answers
65 views

Basics physics question about calculating resistance

Why is the total resistance calculated differently when resistors are in parallel, compared to when they are in a series? For example, $$ \dfrac{1}{R_t} = \dfrac{1}{R_1} + \dfrac{1}{R_2} + \ldots + ...
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3answers
98 views

Two identical DC power supplies in parallel for redundancy?

I'm trying to design a power backup system for my saltwater aquarium. In short, the system will be powered by a 12VDC power supply while the mains power is on. On power failure, the system will ...
1
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1answer
66 views

What happens if you put two coils in parallel

I want to build an LC-Filter from a tutorial I found (German language, if anyone is interested, I'll add a link). In that tutorial, a 330uH Coil with a max amp of 1A is used. I have some 330uH ...
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1answer
43 views

How to sum resistors in parallel and series?

I know how to add resistors in parallel and resistors in series, but i don't understand how to differentiate between resistors in the format shown: simulate this circuit – Schematic ...
0
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1answer
32 views

What resistors to use for 60, 8000mcd LEDs, with 4 * 1.5v battery source? [duplicate]

I currently have 60 LEDs in a parallel circuit. I am using 4 1.5v batteries as the source. The LEDs have a forward voltage of 3v-3.4v (8000mcd, wavelength 460nm). My questions are: Can I just use ...
1
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1answer
53 views

Parallel connection of two 2-ports

In the N-port theory, it says that the total admittance matrix for the parallel connection of two 2-ports is the sum of individual admittance matrices "if it is possible to connect them in parallel". ...
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3answers
109 views

When will parallel LED voltage drops become an issue

The following circuit will cause problems because of voltage drops: simulate this circuit – Schematic created using CircuitLab It should be changed to look like this: simulate ...
3
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1answer
79 views

Is there a limit to the number of parallel LED if each has its own resistor?

I am building a circuit with 6 parallel LEDs, powered by 5 volts through a transistor array which can provide 300ma. If each LED is allowed 20ma (by setting the correct resistance for each), I should ...
-3
votes
1answer
54 views

Maximum inductance of parallel circuit [closed]

Three inductances, 1 henry, 2 henry and L henry are in parallel. Find value of L such that the equivalent inductance is maximum. At this value of L, what is the value of equivalent inductance?
0
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1answer
58 views

diode and resistor in parallel with resistor

how do you calculate V\$_{R3}\$ in the circuit below? V\$_{in}\$, all the resistor values and the type of the diode are known. By simulating this circuit one can see that V\$_{D}\$ is increasing ...
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2answers
66 views

voltage divider in series and parallel circuit

I have these two series and parallel circuits and I want to know how I should find the voltage through R1, R2, R3 and R4. I know I should use the rules of voltage divider but I don't know how when I ...
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2answers
85 views

How do I calculate voltage using the complete diode method?

Doing extra examples for a electronics class, came across a section uses the Complete Diode Model (We haven't covered it in class in much detail, only the definition). The question is: Determine the ...
0
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0answers
36 views

Operating different current batteries in parallel with a UPS

I have a 24V UPS and I use a pair of 12V batteries in series, each with the same current rating (130A). Often I charge the batteries with an external 24V charger to achieve a faster charging time. I ...
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0answers
45 views

Wiring 2 audio output transfomer secondaries in series or parallel

I want to know if wiring 2 audio output secondaries in series is doable. See problems with this schem? Would parallel be a viable alternative?
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2answers
47 views

Connecting power sources in series or parallel?

Basic question: Lets say i have two power sources, one supplying 1V and 100mA, the other supplying 2V and 200mA What would be the difference if i connected them in series or in parallel? As far as ...
0
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1answer
41 views

parallel rlc voltage source

I am learning about circuits and I have some questions regarding circuit initial condition: - no initial energy stored before switch is closed - there is current at L1 at t = 0- I am wondering: ...
0
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3answers
69 views

Should I wire my electrical actuators in series, parallel or a combination of both?

I'm working on a project that requires four (4) electrical linear actuators to work together. They must be driven at the same speed, simultaneously. Let's assume that I have four identical actuators ...
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1answer
49 views

Circuit redraw. Series and parallel resistors [duplicate]

I just wanted to ask you if I redrew the circuit correctly and if you could help me what to calculate first or if you could help me to redraw this circuit even simpler. And to tell me a few tips for ...
0
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2answers
61 views

Equivalent resistance of resistors

Can somebody help me solve this. I need to find the equivalent resistance of these resistors. I really don't know where the trick here is. If somebody could help me I would really appreciate it
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1answer
71 views

Series parallel resistor. Circuit redraw

Can somebody help me redraw this circuit so it'll become easier to see what resistors are in series and what in parallel. Thanks in advance Have I redrawn the circuit correctly. Are R1 and R3 in ...
1
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1answer
115 views

eMMC interface : Parallel vs SDIO

I want to use an eMMC card for my application. After searching on different websites,I was not able to find any parallel interface supported eMMC chip. Is parallel interface available for eMMC ...
10
votes
4answers
785 views

Why do we use two parallel capacitors in a voltage regulator circuit? [duplicate]

C1 and C2 are parallel capacitors and their total capacitance is 1000.1 uF. I think C1 is ...
-4
votes
2answers
85 views

Wiring 5mm IR LEDs in parallel [duplicate]

Im trying to wire 9 5mm IR leds in parallel using a 9V battery. the forward voltage is about 1.5 and Im looking for about 100mA instead of the ussual 20mA with a standard LED. When I punch these ...
3
votes
2answers
108 views

What Circuitry is needed to charge in parallel, but power in series?

simulate this circuit – Schematic created using CircuitLab I've read several other battery posts, and didn't find the answer I was looking for. My question is, can the Diagram I've ...
2
votes
3answers
116 views

LEDs in parallel [duplicate]

If I have 4 identical* LEDs wired in parallel to a single resistor so that the overall current available is 30 mA, do I still run the risk of premature burnout? The LEDs peak forward current is 30 mA. ...
0
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1answer
80 views

Can devices be added in parallel indefinitely?

I'm assuming not, but say you added devices with the same resistance in parallel. All I've learned is that they would receive the same voltage and the current into and out of the voltage source would ...
1
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1answer
26 views

Photomultipliers in Parallel

I have a photo-multiplier going into a preamp then two stage shaping amp (PC250 and PC275 board from Amptek). The photo-multiplier is attached to a plastic scintillator and then a beta emitting ...
-3
votes
1answer
114 views

I want to use many parallel LEDs. Can this IC (BP3309) help me to control them? [closed]

I want to use many parallel LEDs. Can the BP3309 IC (datasheet in Chinese) help me to control the LEDs? I want consistent brightness.
2
votes
2answers
111 views

Help to join 3 resistors in parallel into 1 (power equiation?)

I want to join 3 resistors connected in parallel into one. Like this If for the total resistance I use Rt = R/3 But what about the power of them?
0
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2answers
77 views

Circuit analysis (Intro to Parallel Circuits & Series)

We are just in the beginning phases of learning how to simplify circuits by finding equivalent resistance. I've gotten every problem right except for this one. The answer says its 2000 ohms, but I ...
2
votes
2answers
210 views

Old Text Book Current Question [closed]

Can anyone help my 13 year-old with an assignment? I have little knowledge about electricity and I need to teach her about circuits. We have a question from her seventh grade science book that has us ...
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votes
1answer
91 views

Why is wiring some LEDs in series better than wiring them all in parallel?

I noticed a lot of guides for making an LED array or matrix prefer to wire their LEDs in series first and then wire strips of leds in series in parallel. What is the benefit of this Vs wiring them all ...
0
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4answers
159 views

Capacitors in parallel without resistance

For the following circuit, at time 0, the switch switches from A to B, figure out the voltage wave form at B. The question I am concerned with is whether the voltage across the capacitors will ...
1
vote
1answer
86 views

Can i double max current drawn, putting batteries in parallel?

Im dimensioning a quadcopter,and from my math, everything will draw a maximum load of 58-63 A. I need to choose Lipo batteries that can handle that current draw. From what I know: Max current: ...
1
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2answers
50 views

Parallel Piezo Pickup Problem

I've an electronic drum machine - which involves electronic drum pads with piezoelectric transducers in them (which pick up you hitting the pads with your drum sticks) which feed into a magic drum ...
0
votes
2answers
28 views

Help connecting solar cells to be 12 V

I just purchased a lot of 40 solar cells each with 1.8 W, 0.5 V, and 3.6 A. This gives a total of 72 W. Ideally, I would like to connect the cells in a manner to yield 12 V. I know I can connect two ...
3
votes
1answer
49 views

Capacitors in parallel

I am using a old disposable camera to charge and discharge my Cap. I got 4 Caps and Connected them in Parallel (Hots to hots as is Grounds to Grounds). Can I use this just like normal? Can I just hook ...
2
votes
1answer
55 views

Parallel bus trace width and spacing

I have been working on designing a PCB for a Z80 computer that I plan to sell a few times for interested people. The Z80 will work at a maximum of 8 MHz and has parallel lines going to a system ...
1
vote
1answer
56 views

Connecting different batteries in parallel - how to calculate the voltage?

I have an exercise: I have two ideal battieries connected parallel: simulate this circuit – Schematic created using CircuitLab I calculated a resistance of the whole circut: 0.666 ohm. ...
1
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1answer
156 views

Review my PCB? Mosfet to parallel leds

Can someone please review my PCB? Simply, I'm running 24 IR Leds at medium power, from a 5v arduino MCU pin, all pulsing together (38khz). Big fat traces, lots of space, SMD components. The LEDS ...
0
votes
1answer
100 views

How to drive paralleled mosfets with a microcontroller? [closed]

I want to make a DC switch with mosfets as follow: Now I want to know does this circuit work with reliability? And I want a circuit between avr microcontroller and this circuit to drive the mosfets ...
3
votes
2answers
510 views

Smartest way to charge 18650 batteries when they are used in series

I'm wondering how I could/should charge the 18650 batteries used in the following circuit. I want to charge them via USB in a power bank case like this. But I probably won't be able to use the ...