Tagged Questions

More than one of a thing, performing the same task simultaneously

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0
votes
3answers
75 views

Can I just connect two CR2032 batteries in parallel?

I'm designing a device with a small current draw that will mostly sleep in a very low power mode and I need to use button cell batteries due to a limited thickness. I would like to double time between ...
1
vote
1answer
55 views

How will unmatched lithium-ion cells in parallel react?

We are stocking a portable power pack for USB charging. We tested them when they first arrived and found no issues but after 3 months we tested some of the remaining stock and found about 50% of them ...
1
vote
2answers
146 views

Voltage not dropping in circuit

This schematic shows the circuit that I'm trying to build. At the moment I'm not using V2, as I'm having a problem with V1. From my understanding the diode should drop the voltage by about 0.7V, and ...
0
votes
1answer
76 views

Series and parallel transformers?

I have two different transformers. The output of the first one is 15 volts and 1500 mA. The output of the second one is 5 volts and 500 mA. If I connected them in series (to get 20 volts) what will ...
0
votes
1answer
104 views

Connecting batteries in parallel (concerns)

I have been trying to understand if it is possible to connect two identical batteries in parallel (same: number of cells, manufacturer, capacity, CRate, usage). I want to create a circuit to select ...
0
votes
3answers
82 views

Why do different colored LEDs interfere with each other when connected in parallel? [duplicate]

My very basic electronics education has taught me that parallel circuits are equivalent to separated circuits. To my surprise, when I was playing around with some electronics I found the following: ...
6
votes
4answers
626 views

Is a two-element circuit series or parallel?

Is the voltage source in series with the resistor or is the voltage source in parallel with the resistor? If the voltage source is in parallel with the resistor, then why do they share the same ...
0
votes
1answer
64 views

Calculating R with 2 resistors parallel

I've ran into a slight confusion. The equation for resistance in a parallel circuit should work for any number of resistors, I assumed. So when I'd have 2 resistors in parallel, total Rt would be: ...
10
votes
3answers
881 views

Parallel Capacitor Conundrum [duplicate]

I have recently taken on a project that involves improving a circuit and there is a couple of instances where there are two capacitors in parallel with each other. The values of these capacitors ...
4
votes
2answers
333 views

For the resistor circuit shown in the picture, what must be the missing resistance to give a total resistance of 252 ohms?

After my calculations, I keep getting 1100 ohms, but the back of the book is saying 85 ohms. 85 seems to fit in better with the other numbers, but I can only get 1100 to add up. Here's my ...
-3
votes
2answers
62 views

Parallel circuit with equal resistance?

If a parallel circuit has 3 paths, all the same resistance will the current divide by 3, and will the voltage throughout all of those paths be the same?
0
votes
2answers
72 views

Can you use rectifiers from different transformer sources in parallel?

Consider following circuit: simulate this circuit – Schematic created using CircuitLab It uses two transformers, rectifies their output separately (so that they can't interfere), filters ...
0
votes
1answer
88 views

Can I control multiple stepper motor drivers from one controller?

I need to drive 6 stepper motors in open loop with 1/4 microstepping. The application requires all 6 motors to move by the same number of steps at the same time. There are no sensors of any kind on ...
0
votes
3answers
109 views

summing op-amp: 2 voltages in parallel

I didn't quite get how this circuit from falstad works: http://www.falstad.com/circuit/e-amp-sum.html Specifically, how can 2 voltages in parallel add up when negative input (ideally) has infinite ...
2
votes
3answers
185 views

Is there a GPIO IC that has a parallel interface?

Sorry if this is an obvious question, I come from a software background and don't know the names for a lot of components. I am designing some custom hardware based around a W65C02S processor (a modern ...
-1
votes
1answer
81 views

How to optimize wiring of Christmas lights in parallel and in series? [closed]

Suppose we want to wire some Christmas lights. Should we do this in parallel, series, or both parallel and series? The answer is both parallel and series since if every light was in parallel the cost ...
8
votes
3answers
787 views

Can I solder a wire between two leads on a PCB to make up for a trace that isn't wide enough?

I have a PCB that has 2 traces on one corner who's width only supports a ~10a load. I need support for a 20a load. Actually, it really only needs to support a 15amp load but I'm trying to build in ...
1
vote
1answer
349 views

12V LED strips in series with a 24V power supply?

I am purchasing 50x - 1Meter / 12V / 72 LED /Rigid SMD 5730 strips directly from china. I don't know the LED manufacturer, nor the resistor being used. (yes, this is a gamble) The strip is one that ...
1
vote
1answer
199 views

Resistor in series and capacitor in parallel to ground

Could somebody tell me why someone would need circuit like that in supply rails? I assume it is for making DC voltage smoother by parallel capacitor. However, my 24V power supply has 500mA output ...
1
vote
3answers
95 views

Paralleling power supplies for higher current

I am looking at using two Cincon (CFM80S240 and CFM60S240) power supplies in parallel to achieve a higher current output. Is this possible? If so, can I just hook them up in parallel, or is there some ...
0
votes
1answer
31 views

Resonant frequency in parallel

I'm currently learning about resonant frequency and harmonics under ac theory in tafe, and I've read a few things about resonant frequency in parallel, and it seems as if impedance at resonant ...
1
vote
1answer
189 views

What capacitors do when it is connected in Series and parallel to a AC input

I have seen in many circuits the capacitors are connected in series and parallel with the AC line. What the capacitor actually does when it is in series and parallel. I know capacitors passes AC ...
0
votes
2answers
71 views

Finding load resistance to achieve max power transfer

1) So, to find Thenevin equivalent resistance, R-Th, I disconnect R_L and disable the voltage source by shorting it out. ...
-2
votes
2answers
92 views

Understanding circuit : Output of a CD4017 with 1N4148 diode and RC circuit

I'm reading a circuit on a magazine (look at circuit below) and i don't understand , why the author put a 1N4148 diode and a RC circuit at the output of CD4017 , what is the operations of the RC ...
0
votes
2answers
88 views

Debouncing - Parallel RC circuit?

I was unable to understand two parts of a circuit in a magazine, where you can see a resistor R4 and a cap C8 to ground for—I guess—debouncing purposes, but can't see how it works. The ...
1
vote
0answers
132 views

Charging batteries in parallel when they are connected in series in the circuit

I've got two LIR2450 rechargeable 3.6v coin cells. These need to be connected in parallel to form a 7.2v current which is being regulated down to 5v to power an ATMEGA328P. I need to charge the two ...
0
votes
0answers
60 views

3x CAT4101 parallel with CREE LEDs

I've tested the LEDs with one CAT4101 and they work great, but now it's time to dial it up a notch. I've now got three CAT4101's wired up in parallel to give me 3A to drive two 10W CREE LEDs in ...
-5
votes
1answer
88 views

Series and Parallel Circuit

In the following schematic, if R1 = 42ohm, R3 = 33ohm, VT = 220V, and IR2 = 1A How do I find R2? simulate this circuit – Schematic created using CircuitLab
0
votes
1answer
79 views

connecting oscillators in parallel to increase current

I am trying to power an alternating current coil, and was wondering if I can connect the output from transistor oscillators in parallel to increase the current, like you can with batteries. I don't ...
0
votes
1answer
170 views

Real power and power factor for resonant RLC parallel circuit [closed]

I have no problem finding parts a, b and c, however I don't know how to get part d. You don't have to solve it for me(although it'd be greatly appreciated), but please give me somewhat of a hint or a ...
0
votes
2answers
193 views

Fast rectifier diodes in parallel at SMPS

I'm trying to build a 35 V @ 10 A SMPS. I don't have 15A diode to rectify the transformer output. Can I use two BYW29 in parallel? They are rated at 8A. I know that when diodes are in parallel, the ...
1
vote
1answer
112 views

Voltage on circuit input different than on power supply

I'm using a really good 5V-35A switching power supply to power some mini PCs (Cubieboards if that matters) as below. simulate this circuit – Schematic created using CircuitLab The weird ...
0
votes
1answer
66 views

How to put a battery and battery charger parallel in a circuit

I am making a speaker that runs at 3-5.5 RMS and I need a battery to supply power to it and so I got a house phone battery pack with a diode now I need a way to charge this so when it is charging that ...
2
votes
1answer
283 views

LED wiring questions with 9v battery as power source

My son is working on a project in which he is using 36 total LEDs consisting of 7 different LED's. There are 6 different solid colored LEDs varying from 1.88v to 3.2v and one color changing that is ...
4
votes
3answers
754 views

Is it good practice to parallel relay contacts for increased current capacity?

Say I have a DPDT relay, like T92S7D12-24. The contacts of this relay are rated for 30A, but there are two sets of contacts. Can I parallel the contacts to get an effective 60A relay? Further, could I ...
0
votes
1answer
157 views

Two L298N for two stepper motors

I have two stepper motors (ripped from old scanners) and two L298N ICs. I have to connect these motors to the STM32 MCU, and I'm going to use this scheme: I want to make one board for two motors ...
0
votes
5answers
365 views

Circuit capacitance question

Given the following circuit, what ways there are to calculate its total capacitance? Thing is this is not a simple case, and I can't really decide which part is parallel and which is a series, ...
1
vote
3answers
230 views

How do you set the reference voltage for a comparator?

I know this is certainly a beginner's question but am a first year student so hopefully I can be forgiven. I was looking through a electronics booklet provided by IKES website, and it's talking about ...
1
vote
2answers
147 views

How to get higher amperage out of a power supply?

I currently have a 24V - 5A power supply in a commercial product that may require upwards of 8A from the load. Ideally, I would just hook up another 24V - 5A power supply in parallel and not worry ...
0
votes
1answer
370 views

Charge at 24v and discharge at 12v for battery system

Is my thinking correct. Below is a simple diagram of the concept I want to check. Is this: 1: Possible 2: Feasible? I.E are there any concerns or foreseen issues with this design? Edit:
1
vote
4answers
153 views

How can I control a LED with two separate control circuits?

I have a LED controlled by a microcontroller. I want to know how I can bypass this microcontroller so that I can control the LED with a separate current. Would I use transistors to switch between the ...
1
vote
1answer
100 views

I am failing z-parameters, but I don't know why

I need your help to see where am going wrong. A two port network driven at both ports such that the port voltages and currents have the following values: \$Z_0\$ = 50 ohm \$V_1\$ = 10 < 90 - ...
1
vote
1answer
123 views

Can I get 7A of current from two 3.5A rated batteries (without an increase in V)?

I have two variable batteries with the following specs: Li-polymer Capacity : 20000mAh / 74Wh Input (for charging) : DC 15 - 19V (1.3A max) Output : DC 12V / 4A DC 16V / 3.5A DC 19V ...
1
vote
2answers
324 views

Connecting two capacitors in parallel

Two capacitors are parallel connected with an open switch. Both have a different capacity in which: $$c_1>c_2$$ and both charged with a different voltage $$v_1\neq v_2$$ and now we close the ...
2
votes
3answers
416 views

Parallel LCD screen to serial? (1 dedicated microcontroller?)

I'm a newb with electronics and was wondering if there's an IC or PCB that could convert a parallel LCD connection to Serial so I can use 2 wires to communicate with the screen using an arduino and ...
0
votes
3answers
107 views

How to gauge resistance on parallel circuit with step down buck regulator

I'm trying to create a circuit with two loads in parallel ( essentially piggy backing one circuit on the power supply of the other ). Circuit 1, the main circuit requires ~900ma at 12v. Circuit 2, ...
5
votes
3answers
446 views

crystal oscillators connected in parallel

why there are two crystal oscillators connected in parallel in the circuit above? i am familiar with the configuration of Q2( look at the schematic) but what is the purpose of Q3? do i really need ...
1
vote
2answers
119 views

Connecting nine LEDs

I am making a small project for myself but have very limited knowledge on electrical engineering (V=IR is about all i know). I want to power nine LEDs (max 28 mA, 2.25V) with one battery. Do i connect ...
2
votes
3answers
377 views

Can someone explain this simple schematic? (capacitor with voltage regulator)

Please understand that i am actually a really beginner in electronics. I found a really nice topic on how to create a 5V DC from a 9v power supply. All is ok. But in order to smooth out ripple, the ...
0
votes
3answers
126 views

Why does a voltmeter show voltage drop

Consider this circuit. What would I get if I measure over R1? It should be less than 12v, right? But then what volatage is LAMP1 running at? Is it still 12v, or is it the voltage I measured across ...