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Questions tagged [dc]

DC stands for Direct Current, which means the flow of electric charge in a single direction. Examples of a DC source are batteries, solar panels, dynamos.

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40 views

Using an AC rated light switch for switching DC logic level voltage

Would it be safe and within electrical code to switch logic level DC voltage using a standard AC light switch? I know high power DC lines can create arcing with a switch of that style but low power ...
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1answer
76 views

Can I use a capacitor which has 275v +-10% tolerance in a 9V circuit?

I am trying to get parts for a circuit i want to make and I'm very new at making circuits. As a result i'm unsure if i can use a 150nF capacitor with 275v+-10% tolerance in the following circuit or ...
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3answers
36 views

Looking for a dc 2pin connector with latch [closed]

I'm looking for a pair of connectors with following features. about 10V rating (no high voltage) 5A 2 pins latch which will prevent from accidential unplug panel mount I want to mount the socket on ...
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1answer
101 views

best choice of a stepper motor to lift a 3kg load [closed]

first time working with a motor.am designing an egg incubator and need a stepper motor to tilt the egg tray at 45 degree occasionally.there are two egg trays each is attached to the incubator wall and ...
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1answer
1k views

Motor current consumption and power do not match

I am working on a design and need to calculate the energy consumption of this motor: https://www.maxonmotor.com/medias/sys_master/root/8825428410398/17-EN-256.pdf. (Part No. 339252) The ...
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1answer
314 views

How many wires can I safely fit into this screw terminal?

I have about 40 positive and 40 negative 18 gauge wires that I am trying to connect to one DC power source. I have a few terminal blocks to achieve this. Each terminal block has 2 rows of 12 ...
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2answers
603 views

Diesel generator consumption formula

I am working on a project to monitor a power meter parameters like voltage, frequency, current and so on and this monitoring for both AC and DC. For DC we are using Cummins diesel generator, now I ...
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3answers
61 views

How does the voltage drop to negative values at t = 0 when the voltage starts with 0 V?

I understand that the voltage in the inductor is 0V because it behaves as a wire with a constant dc source while the switch is closed. But why does it drop to a negative value when the time t = 0 and ...
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2answers
199 views

A few basic questions about simple electric circuits

For beginning, sorry for my english and for long post. But maybe it would be useful for others newbies. I'm trying to understand basic things about electric circuits on my own, and at the moment I ...
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2answers
205 views

AC line from inverter grounded to vehicle chassis

What happens if a hot line from an inverter powered by a vehicle battery contacts the vehicle chassis? This will form a circuit connecting the hot line from the inverter to the negative terminal of ...
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1answer
77 views

Estimating the current consumption of a DC motor

Good day, I am wondering if it's possible to estimate the continuous current consumption of a DC motor vs startup or rated current. I am trying to put together a solar powered aquaponics system. The ...
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1answer
45 views

Grounding house battery to vehicle chassis

For a solar power installation in a van/RV, should the negative terminal of the house battery —the battery that is charged by the solar panel and used to power devices and appliances whether or not ...
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1answer
112 views

ESP8266 (esp-07) powered by battary(s) for at least 1 year

Hey all I am trying to see how long I can possibly have a ESP8266 ESP-07 operate with only 1 or 2 of the Lithium Ion Battery 18650 Cell which claims to have 2600mAh. I am making a window alarm sensor ...
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1answer
67 views

Is there a standard that specifies the polarity when using an SMA connector (or similar) to connect a DC power source?

For regular DC power adapters I will see a polarity indicator like the following: However I have seen some RF circuits that indicate a DC power connection to the circuit over an SMA connector but do ...
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2answers
128 views

In an audio circuit, with an LM386 chip - how does the DC electric power and the AC audio work?

I am currently putting together a simple audio amplifier using an LM386 chip. In the midst of studying how this chip works, and the proper circuit analysis behind it, I began thinking about how ...
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2answers
98 views

DC Power Jack - minus to chassis?

Is it OK to connect the minus from a DC Power supply, 15v 4A (switched) to a metal chassi as ground? No electronics will be connected to the chassi. The jacks that I have found seems to be made of ...
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2answers
66 views

Determining minimum safe wire width at high amps in a DC 12V system

In a 12V DC system, given a particular maximum current and length of wire, what is the best method to determine the minimum width (gauge) of that wire? In particular, what method is best for high ...
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1answer
133 views

How to reduce noise in this circuit?

I'm using a Raspberry Pi in a circuit I'm building that includes a few elements. Elements in the circuit: PWM driver to control 3 servos Mic board for recording Class D Amplifier that drives 2x3W ...
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1answer
173 views

Cheapest/quickest way to power 2 x 12v fans from 24v baseboard fan socket?

I have an APC baseboard that runs off 24v. The two fans (2 x 24v @ 0.16A = 7.7W) were a noisy and power-hungry problem. I've got a couple of Noctua fans of the same size, with "almost the same" or "...
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2answers
106 views

Internal Resistances of Capacitors

I have read somewhere on a forum that there are two effective internal resistances of a capacitor in a DC circuit but can't seem to find any further information. From what I read 'parallel resistance' ...
2
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1answer
101 views

solar panels: multiple roof surfaces on one inverter string?

Notice below part of electric scheme as designed by solar company: On the left you can see inverter used - Delta Solivia 7.6 TL (see Operation and Installation Manual for details) which supports up ...
3
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2answers
69 views

Why is the 240VAC-12VDC giving both 12VDC and 26VAC as output?

I was using this adapter to power a 12VDC LED strip and felt electric shock from the output wire. When I measured the output with a multimeter, I found both 12VDC and 26VAC on it's output. What could ...
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0answers
63 views

Does applying dc bias to a signal make it stronger?

I worked on a device that mimics a triode vacuum tube. But it doesn't use any vacuum, instead, it uses an electrolyte. I got several of them working, and I can make them switch, by making the "grid" ...
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1answer
96 views

Measuring the Internal Resistance of an Electrolytic Capacitor

I was wondering if its possible to measure internal resistance of a capacitor from a DC circuit using the below formula and method. \$\ V=V_0e^{\frac{-t}{\tau}}\$ \$\ lnV=-1/\tau\ *t + ln V_0\$ ...
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1answer
68 views

What products can be used power LEDs from an wall outlet? [closed]

I am currently working on a project that will be a type of night light that plugs straight into a wall. What parts can I use to convert the wall outlet voltage into that which can be used by a couple ...
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1answer
176 views

IGBT contactor design

I found this circuit in an older post. I was thinking about using this in place of a contactor to break under load. The load would be at 500V 300A DC. There would be overcurrent protection in line ...
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2answers
118 views

How to power a low voltage LED with a high voltage source?

I have a panel-mount LED (https://www.digikey.ca/products/en?keywords=A-LED8-1GAAS-PR7-1) that is described as "2.2V 30mA" and I would like to power it with a 28V DC source. My questions are as ...
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1answer
141 views

Electrolytic Capacitor Internal Resistance

I'm doing an experiment to investigate the internal resistance of an electrolytic capacitor in a DC circuit. Doing this I am measuring the discharge voltage against time, finding tau and from there ...
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1answer
122 views

How to map 0.40-1.87V to 0-5V? [closed]

I cannot seem to wrap my head around this. I have read about using an instrumentation amplifier, however even then I am not sure how to use this in this scenario. Could someone explain to me how to: ...
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3answers
235 views

Current limiting resistor on peltier element

I have a 12v/22A DC switching power supply and 9 peltier elements rated for 12v/6A. I would like to limit current to 2A per peltier element. I don't know how to calculate the impedance (in ohms) ...
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1answer
48 views

Nest Protect gen 2 battery to POE

Hey all i am looking for some advice in how to go about my project with a Nest Protect gen 2. In my home i have ran cat6 wire to all 3 locations that require a smoke detector. These cat6 cables are ...
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3answers
58 views

What could be the transmission loss per metre of using DC current for a low voltage solar system?

I think that it shouldn't be much but I wanted to get a ballpark numerical figure. We've installed a 2kW solar power unit at our home, which is installed on our rooftop. To convert the DC current ...
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2answers
85 views

Unreliable switch on string of LED lights

I have a string of LED lights (think Xmas tree lights) powered by a wall wart (3.2V 1A) and turned on and off with a simple inline rocker switch I had troubles with the lights flickering and ...
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4answers
2k views

12V DC to 12V AC (50 Hz) Converter / Inverter for low loads (< 1A)

I am building a mobile Sound System powered by a car battery. I have a small mixing table that runs on 12V but it needs AC Power (50Hz) and won't work with DC (I tried that, with very weird results). ...
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1answer
194 views

0-9 V DC to -9 to 9 V? [closed]

I have a DC signal going from 0 to 9 V. How can I rescale it to the -9 to 9 V range? enter image description here I have infra red sensor , this sensor is damaged , this sensor generate _9 to +9 DCV , ...
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3answers
288 views

How to protect H-bridge from burning

I'm building an H-Bridge to drive a 5v DC motor. We made the circuit with SMD components And everything works properly. But the problem arises when the motor output gear is held manually. The motor's ...
2
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1answer
26 views

Co-application of DC field and Microwave Irradiation on Soil

I am attempting to design/enhance a system which applies direct current to a soil for the electro-kinetic remediation of organic/metal contamination. My current plan is to try enhancing conventional ...
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2answers
192 views

How to dim my dc push button led switch that is too bright?

Attached is a screenshot of my button and the dimmer I found, it’s getting a 12V source. I figured using wiring the pwm dimmer like the one shown will work. Please let me know your suggestions on if ...
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3answers
443 views

Square wave to DC voltage with passive components

Good day, I have a design challenge that I have been thinking about. Is there a passive and inexpensive system that I can get a square wave (frequency not decided yet, but less than 8MHz) that will ...
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1answer
48 views

Problem with voltage between a DC step up and Raspberry

I am working with a DC step up (XL6009) and a battery for the cell phone (3.8V), with a capacity of 2800mAh to power a Raspberry (10 minutes maximum). The output voltage of this module (XL6009) can be ...
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1answer
89 views

Snubber Network Over a Switch

I'm a newbie to electronics even though I have been working on them for a few years in mostly a hobbyist setting. I'm posting here for the first time so please be gentle. The problem I'm having with ...
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0answers
259 views

How can I design a 12V DC UPS circuit using NMOS?

I have an NMOS with me so I tried to design this 12 V DC UPS circuit after looking at another similar PMOS circuit, but when I open the dc switch, the output is 18kV!! What is the problem with this ...
23
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2answers
4k views

Why does inverter synchronization with the grid take 5 minutes?

We had some solar panels & an inverter installed recently. Every time the inverter is turned on (after maintenance or with the first light of the day) it has to synchronize its generation phase ...
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0answers
32 views

DC Machine Armature reaction, how saturated iron core affects the armature reaction effect?

I understand the current induced in armature winding makes it to induce EMF in it but in a book there is given something I can't correlate with my understanding. "it causes no change in flux/pole ...
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0answers
62 views

Need help to design a voltage regulator circuit for two 3v dc motors

I intend to use two DC 3V motors to make a mini water pump as described in this video. Here are the specs of my solar panel which i intend to use as power supply for the circuit: Voltage at max ...
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0answers
103 views

Use of DC source in Zener clamping circuit

A question in my engineering degree asked me to design a clamp circuit that gives a 10V 50Hz AC signal a +5V DC bias. I designed the following circuit as my answer: I assumed 0.6V forward drop for ...
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1answer
60 views

Design of SMPS for running 10 bldc motors [closed]

I want to run 10 motors, each motor has specification of max 70 V and max current 160 amps. My doubt is, is it possible to build SMPS for these purpose. If not what would be the best alternative. I ...
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0answers
51 views

12V Converter for li ion battery pack supporting 16-20 Amps

I built a 4S Li ion battery pack and I need 12V output at 16-20Amps but I have limited space (70mmx55mm). 12 V would be the best but I could also just reduce the max output from 16.8V (4x4.2V) to ...
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2answers
1k views

How much voltage does a 12V led strip need to light up? [closed]

I'm designing a photovoltaic powered installation. In my current design, I'm using a 12V battery, and I intended to power the lighting directly at that voltage without the usage of an inverter. I ...
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votes
1answer
49 views

Running a DC motor through a bicycle and charging a battery [closed]

I am running a DC motor through a bicycle and charging a battery. Does battery gets charged while pedaling in both the directions? I observed from voltmeter one is negative voltage. I am novice in ...