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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7answers
825 views

Avoiding DC voltage drop over long distances

I am trying to power my IP camera over a long distance from the power socket (about 10m). The included power adapter, rated for 5V 2A is about 1.5m long. I cut the cable and extended it using a ...
7
votes
5answers
2k views

DC adapters: why so few amps?

If I have a device that draws 5 amps at 12 volts, I can use any 12 volt DC adapter that can provide at least 5 amps. Why don't all DC adapters have the capacity to provide loads of amps!? If all DC ...
0
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2answers
47 views

LM2596 minimum input voltage question

I'm trying to feed the LM2596 (DC to DC) booster a 9V battery. Now, I see that it has a minimum voltage required of 3V. My question is this: What happens when my 9V battery drops below 3V? Would ...
0
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2answers
76 views

Power supply with 10 VDC and 2mA

I have device need 10 V DC and 2 mA, can I use DC battery? For example, two batteries with 5 V DC and 1000 mAh?
1
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1answer
74 views

24V to 5V DC conversion for Raspberry Pi

I'm trying to power several devices off of a breadboard. For simplicity I want to power these all from the same PSU. The highest voltage amongst the devices is 24V. I was looking to use a 24V 2A ...
0
votes
1answer
56 views

How to supply multiple 12V DC 3 amps motors?

I need to supply four DC motors 12V @ 3 amps with a battery pack. I was wondering which characteristics should have an hypothetical battery pack to supply all four motors together. How many volts ...
1
vote
0answers
74 views

Insufficient Power when using one power source vs two [duplicate]

So I've been working on a wireless remote relay switch using several components and have struck a break wall. The issue I'm having is that the D0 siginal output triggers the relay but only at short ...
1
vote
2answers
86 views

Using a DC voltage as the base for a transistor to amplify AC Voltage

I'm a little new to electronics, particularly transistors, so I don't know a lot of the different types and inner-workings of them. I have a diagram which, hopefully, will gradually increase the ...
2
votes
1answer
108 views

Electric motor will only start turning at lower voltages

I have a tiny DC motor directly connected to this power supply. The motor starts just fine when the supply is set to 4.5V. I can then change the voltage to 6V and it continues to run just fine. ...
4
votes
1answer
166 views

Headphone output: DC Bias?

Need some electrical advice, as my days of my Electrical Engineering degree are well behind me... I have 4 PMR446 radios ("walkie-talkies"). They work great, but when using an earpiece, every-time ...
0
votes
1answer
59 views

How create a low-voltage boost (~4v to 5v)

I am looking for a circuit that will go from a Li battery that has a voltage between 3.6v and 4.3v up to 5v - and I have seen similar questions such as this and this, but those just recommend ...
2
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2answers
96 views

Measuring current around 20 amps

I have an electrolyzer that works with car battery (12 volts DC) and draws current around 15 amps. I have a digital multimeter that can measure 10 amps at most. So how can I measure the current? Maybe ...
0
votes
2answers
42 views

What is the effect of the rated current for a breaker when a 230V 6A rated circuit breaker is used in a 24 V DC circuit?

I want to use a normal household breaker for connecting to a 24V circuit. The input supply is a 230V AC to 24V DC SMPS. The output of the DC converter is connected to a load (rated 180 milliamps @ 24 ...
0
votes
1answer
49 views

Full wave doubler difference and connection of neutral and phase

I'm testing a circuit for creating am unregulated "HV"DC source. The circuit is like this: simulate this circuit – Schematic created using CircuitLab The example I'm using uses a Variac ...
0
votes
1answer
124 views

AC voltage gets mixed with DC

I am using ATS (automatic start) for my generator. Its programmable IC goes out of work after 2 or 3 days and I have replaced 3 ATS card. My card supplier says that you are somehow getting AC voltage ...
0
votes
2answers
93 views

How to select most efficient motor for generator?

First post. Please forgive me if this is a stupid question. This post can be broken down into two questions. I am building a bicycle generator, but am new to the field of EE. I am trying to select ...
0
votes
2answers
169 views

How to amplify DC Voltage to be used like supply to 2km?

I want to turn on a device away from the voltage source to 2 kilometers. My device operates at 24VDC or 48VDC / 35W. I need to know how is it possible to amplify the voltage from 24Vdc to 240Vdc or ...
0
votes
1answer
69 views

Good volts and amps but phone still charging slowly

I am really new to the EE game and am still tinkering. I have built my own portable DC power source similar to a Minty Boost from scratch and plugged it into the USB port of my Galaxy S3 and it ...
2
votes
2answers
96 views

Circuit to pass voltages above a threshold level

I have a sine wave signal centered around 2.5 volts (1/2 Vcc) in which I require the the upper half only, brought down to 0 volts, so a 2 volt peak-to-peak input around 2.5V would become a half sine ...
0
votes
1answer
34 views

Can the volts and\or amps in a repalcement DC power cord vary without problems? [duplicate]

In general I've always wondered about this but now I have lost the DC power cord to my portable speakers. The manufacture does not have a replacement or at least one I can find. The specs are 12.5 V ...
0
votes
1answer
72 views

24v 450w DC motor powered electric bike connected to a lith-ion battery pack (56v 6.5a)

How do I prevent the DC motor from burning out using this battery pack?
0
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2answers
102 views

What wattage solar panel required for AC 1000 watts

If my house load is 1000 Watts AC/220V, then 1000 Watts DC/12V solar panels is not enough. What wattage solar panel would be required for AC 1000 watts?
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3answers
484 views

How many Watts DC are equivalent to 1,000 Watts AC? [duplicate]

How many Watts DC are equivalent to 1,000 Watts AC? For instance, my load in AC is 1,000 Watts 220V. Then, how much DC watts would an equivalent load dissipate in 12V or 24V DC system?
0
votes
2answers
61 views

Control automotive AC switch via TPS voltage

The A/C compressor is engaged via a single wire that comes from the 'A/C' button on the dash board. I want the A/C button to disengage when the throttle is at 50%. The throttle position sensor (TPS) ...
0
votes
3answers
159 views

Grounding a capacitor?

Noobish question. I'm trying to make a dc variable voltage power supply. I will include the schematic which I am trying to build. In the schematic there are two 1000 uf capacitors which I believe are ...
0
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3answers
82 views

Diode in parallel with two DC sources

Please help me to find the answer for the following question from Flyod 9th Ed. Determine the voltage across the diode in the following figure, using the complete diode model with r'd = 10 Ohms and ...
1
vote
1answer
68 views

How do I replace an existing servo with a geared DC motor?

I am a complete beginner, just getting into the world of electronics, in particular robotics. I have found a really nice open source set up that I want to build on and change for my own ends. The ...
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vote
4answers
169 views

How to drop 240V DC to 5V DC

I would like to drop a 240V DC voltage to a 5V DC voltage to supply electronic. The 5V stage needs less than 5mA in current. The solutions I looked at are: Resistor divider (Not really ...
0
votes
0answers
50 views

How can I use a 9v chaser board to run LED strips

a few years ago I bought an LED sequencer circuit board kit. Once assembled you can adjust the pace and the brightness with 2 POTs of up to (I think) 8 LEDs. this board runs off of a 9v battery and ...
0
votes
1answer
80 views

3V and 5V supply Topology (Embedded Design, Mixed Signal)

I am developing a mixed-signal embedded system that requires both 5V and 3V rails. The 5V rail powers an analogue sensor and a precision ADC. The nature of the sensor is such that its output will be ...
0
votes
1answer
39 views

Varistor over clamping voltage at DC

First of all, I know I should not use a varistor at a DC level higher than its clamping voltage, but I want to do it for a test (destructive or not). What I want to know is what is the maximum current ...
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vote
6answers
198 views

Why do cables and batteries have a positive and a negative side?

I am a beginner in electronics, mostly self-taught. If electrons are negatively charged and are the reason for electric current why is there a 'positive' side on a battery and negative one? Don't ...
2
votes
1answer
88 views

DC current stopper [closed]

I don't really know what I am looking to make is called so I am going to try to explain it. I set up a motion activated light in my room. The lowest time interval is 60 seconds and I am okay with ...
0
votes
1answer
64 views

DC motor spun clockwise then counter clockwise creates AC current?

I am making a generator with a DC motor but the style of turning the rotor would be clockwise and then counter-clockwise, and I would want to capture as much current as possible so I hope it could be ...
0
votes
1answer
67 views

Battery pack for DSLR coupler

I am planning to make a battery pack, by using rechargable batteries, that i can use to power my DC-coupler for my DSLR camera. (Ref. Image) On my original camera battery it says 7.4V 1.2A but i ...
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votes
1answer
70 views

VHF radio - Motorola GM340 - could I have damaged it with too much current? Why would it not be damaged by being connected to a 12v battery? [closed]

I connected a Motorola GM340 VHF radio to the 12v DC converter for another radio, an ICOM IC78, which gives 13.7v at 16 amps. The wiring did not have a fuse. As it did not work, I wonder if the ...
0
votes
0answers
37 views

LED bulb that works on both 64 volt DC and 110 AC

Can anyone advise on a reliable/cost-effective way to modify a screw-in LED light bulb so it will run on an AC power supply that has a battery backup where DC is provided in backup mode (this is for ...
1
vote
2answers
103 views

6V DC Motor Overheat

I am totally new to electronics, so be patient with me please, it is very basic question :) I have a 6V DC motor which I reused from an old device, that means I don't know its specs. I connected it ...
1
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1answer
67 views

How can I create a DC-DC voltage multiplier [duplicate]

I want to take the 5V output from a USB port and make it 12V, so that I can run a cooling fan which is 12V. Is there any circuit I can make at home myself? If the output voltage is not exactly 12V, it ...
1
vote
3answers
102 views

Stable power for LED from 5.5 to 7.5V AC

About a year ago I posed the question "Making 12V DC from 6V AC". Since the conversion from AC was going to be problematic (for me), I tackled the tail/brake light first, because working with the 6V ...
3
votes
5answers
426 views

Why do electronic circuits need their power supply to be DC, or rectified AC?

I'm pretty sure the answer to this should be obvious - even to me ... It's been a while I've been reading and attempting to construct simple electronic circuits. The supply almost always is either ...
0
votes
1answer
85 views

How to implement grounding into this electrical circuit?

I'm trying to make some tutorials but I have no idea what should I do when I see the term ground (GND). Here is an example: I want to know how I build the GND part. Where I connect it? Also, if ...
0
votes
2answers
81 views

How to protect bistable latching 2 coil relay with diodes?

I know that a revers diode is required to protect a DC coil relay. But to protect this relay RT314F05? It has 2 coils, are 2 diodes enough?
1
vote
1answer
45 views

Supernode question

I have run into a question while revising for my exam that I can't seem to wrap my head around. I know I have to use a super-node. Which I have circled on he next image. I don't understand why ...
-1
votes
1answer
124 views

Transmitting 12v DC over a long wire

I'm trying to charge my laptop through a 12V battery and 12-19V adapter over a long wire but I've noticed that the adapter makes some noise and doesn't work. On the other hand when I connect it close ...
11
votes
3answers
761 views

What is the difference between a 30 V power supply and a ±15 V power supply?

I need to get a ±15 V power supply and I am wondering where to find it. Should I get a 30V DC power supply in its place?
2
votes
3answers
82 views

DC power through a female socket

I have a solar panel and I would like to use an extension cord. I know this works (heavy duty extension cord) but the guy cut the ends off of the cord to just use the wire (see video links below). I ...
0
votes
0answers
103 views

DC Voltage of a 12V AC transformer after rectification

I want to drive relays using Method 2 of the following question: What is the most economical way to drive an array of single coil latching relays? This basically means that any time the relay is ...
1
vote
1answer
83 views

Is it possible to power an AC-to-DC switching adapter with a DC input?

Typical "wall-wart" switching power adapters are often rated for ~110-240V 50-60Hz AC input and output low-voltage DC. For this question let's assume the output voltage is 5V DC. Internally, the ...
0
votes
0answers
47 views

Drawing 2A from 1.5A source. What are the risks? [duplicate]

I have 220V to 12V converter with 1.5A output. My simple motor draws 12V and 2A. Are there any potential risks, when the difference is so small (besides motor being slower)? I cant figure out if ...