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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What is the difference between these two relays?

1- DC12V Coil Power Relay 10A DPDT LY2NJ HH62P HHC68A-2Z With Socket Base 2- Amico 12V DC Coil Power Relay DPDT LY2NJ HH62P-L JQX-13F 10A With PTF08A Socket Base First assumption is that they are ...
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4answers
412 views

How can I reduce voltage from 40VDC to 5VDC?

I'm working to power a micro controller that requires something like a USB power supply - 5VDC with a normal draw of .75 - 1 amp but could possibly draw as much as 1.5 amps. I know that with smaller ...
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55 views

Identifying DC electrical power connector

I have here a PowerFilm 10 Watt F15-600 Solar Panel, and attached to the panel is this connector: The male end attached to the panel has a little green rubber gasket on it and the female end ...
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21 views

Simple sound pulse (or frequency) to voltage for switch

I am building a tiny project using an android phone -- it simply has to drive a transistor switch on and off. Instead of going down the route of trying to interface to a micro controller via ...
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351 views

DC bias difference between square and sine wave?

I have a 90V DC voltage, VPP. I have a 10Vpp (-5V to 5V), 100 kHz square wave that I'd like to re-bias at VPP/2. Here is the output from LTSpice: Biased output starts at 45V and then 10V is added, ...
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45 views

Should the Gauge of wire be consistent for DC

I'm looking at an ATX Power Supply with 2 rails each with a specification of 12 volts @ 20 Amps. That should be a maximum of 240 watts (per rail). The modular plugs/cables that plug into the power ...
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61 views

Why do you need a thicker wire when wire length increases?

Question: So far I've found that the thickness of the wire influences the resistance. A thicker wire has less resistance. Also, the length of a wire has a linear correlation with the resistance. 2x ...
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37 views

Automatic DC 3 line switch

please help me with an advice. I need a dc switch, but the switch should work from electricity. For example: 2 in lines and 1 out line. One in line is 9 volts and out line is 9 volts, but the second ...
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38 views

Wireless DC Motor & Linear Actuator Control

These are the 2 items that I have: 24V 110RPM 1Amp DC Motor. 24V 100mm Linear Actuator. First Question: To run the DC Motor I am thinking of getting this 24V 2A power supply in the hope that both ...
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1answer
54 views

Arduino SSR 5V DC (Mager GJ-3FA-L)

I just noticed this SSR that was for DCV instead of all the others that are normally for AC. Although I can not find the datasheet for it, it does seem compatible with Arduino. eBay auction site ...
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88 views

L298N damaged? What to do?

I'm trying to control a DC motor with the L298N motor driver and it worked for a brief moment. I've used the setup mentioned in this video tutorial, but someone in the comments said that with this ...
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1answer
79 views

Wild AC to DC for Arduino and high power leds

I've seen some similar posts but none did exactly match. I'm looking to power a Arduino Uno and 1x 10W + 4x 3W LEDs (Using BUZ11 from Arduino output) from a very wild AC source which is on a very ...
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1answer
65 views

DMM Auto-Polarity / Polarity detection

I have understood how auto-ranging is typically achieved on a digital multimeter, but I'm having trouble finding an example of how (DC) polarity is handled. How does the meter know if a voltage is ...
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1answer
25 views

voltage regulator BD9C401EFJ

I am using the BD9C401EFJ for 9V to 5V conversion(with enable pin pulled high). So - I/p = 9V and o/p = 5V. I was just doing some expts and saw that when I give no i/p, and I give 5V at the o/p side ...
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73 views

Will running a DC motor below stall current damage it?

We have DC motors that power wheels on a car. Because of internal friction, the motors will not actually rotate until they are given 50%+ power. However, they do make some neat noises within this ...
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61 views

Solar panel and little computer fan

OK here is the spec: Solar Panel 4"x6" 200mA 7.2v Fan small : 20x10mm, 12vdc, 60mA, 2.17cfm medium : 40x20mm 12vdc, 140ma, 8.28cfm What I'd like to do, is to be able to run the fan hook to ...
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58 views

Board Input DC voltage

I need to receive a 24V signal from an automated industrial system. The receiving board is a UDOO system that its I/Os can handle voltages until 3.3V. Any ideas on how can I make things work?
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80 views

Why does capacitor value changes when capacitor is DC biased?

I have seen ceramic capacitor value varying under various DC biased levels. Dc biased was a huge factor as capacitor value is reduced by 50% almost? Why?
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59 views

Basic question regarding power consumption of different devices

I have current values for devices measured at different DC voltages. 4.2mA at 2.4V 68.8uA at 3.0V 44mA at 2.0V 65mA at 3.4V If I were to power them at a voltage of 3.6V and would like to ...
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1answer
52 views

Differential Drive for Heavy Robot

I'm asking here another question in relation to my previous one. I would like to know how would one proceed when you want to control a heavy robot with differential wheel drive. When it comes to ...
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1answer
52 views

Will a Transformer work from a DC inverter's output? [closed]

If so, is it ever more efficient to use an inverter into a transformer to dial down DC Voltage?
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81 views

What power strategy should I use for this board? [closed]

(Similar but not quite the same question here. ) I'm repurposing an existing synth board which is powered like so: -15VDC GND +12VDC I'd like to power it ...
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96 views

Why are some terminal blocks blue and grey in color

Looking at some terminal blocks like the one below, why are the top level positions color coded blue while the middle ones are in grey? I understand yellow-green are for ground connections. I am ...
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4answers
94 views

What gauge wire for 36V (DC), 5A peak?

I've searched online and found wire gauge calculators but I still can't seem to find a reliable answer. What gauge wire do I need to carry 36 volts (DC) at 5 amps (peak) for 4 meters? This cable ...
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2answers
98 views

How to choose what voltage power supply to use?

I'd like to build a keyboard emulator, and I've found three links that detail the process: 1, 2, 3. Here's the rough circuit: The thing is, across the various articles I've read, people are using ...
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77 views

Can I use 80 white 5mm LEDs with only one resistor? [duplicate]

Can I use 80 white 5mm LED with only one resistor? I use 12 volts power supply (up to 2 amps). I tried 100 LED design but I used 50 resistors (2 series led + resistance). So was a lot of soldering. ...
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60 views

Relay needed for an input ot 0.15 V

sorry about the question but I'm a beginner here. I have a very low DC voltage of 0.15V and I want to use a relay with in a simple circuit to light a LED. I'm learning in how to build circuits. So ...
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109 views

AC and DC voltage are constant even though the frequency changes

In the circuit below, why does the AC voltage remain constant even though the frequency increases?
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48 views

Detecting polarity in a DC device [closed]

I have a device which can be charged with 5v DC. I wish to locate an adaptor for it, but not knowing the device's polarity, I'm stuck. Please note: The device requires 5v DC but has no polarity ...
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3answers
66 views

Switching between several high power DC devices?

I would like to control several high power DC devices (12V DC LEDs). From a tutorial, I found that I can control these using a 3.3V PWM input and a MOSFET. From what I understand, the MOSFET only ...
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1answer
89 views

Op-Amp Sample and Hold Circuit Help

So, I'm trying to modify a sample and hold circuit from "The Forrest Mims Engineer's Notebook", that uses a 353 op-amp, so that it runs off of a single supply: I needed to add a 4.5V (1/2 supply ...
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69 views

Is rms value of a positive varying DC voltage same with its mean value?

I know that rms of an AC is totally different than its mean. But what if the voltage is not alternating(DC) but varying by time. For example a noise with a huge offset. How is varying DC measured by ...
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80 views

Advantages of Isolated DC-DC Converter over non-isolated?

I am trying to understand in what type of situation I will need an isolated DC-DC converter instead of a non-isolated one. What are the design criteria that can lead one to one way or another? In my ...
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3answers
180 views

Power 15 meters of LEDS?

I'm trying to make a display out of 2811 LEDs from China (15 meters long x 7 LED strips). Each strip consumes 18W@5V(3.6A) per meter and I plan to use 7 strips, each 15m long. My calculations show ...
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0answers
17 views

Can dc adapter be used instead of ac for battery charger [duplicate]

I need to replace my ac output adapter radio battery charger and can only find a dc output model with same watts and amps - will this work safely?
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3answers
90 views

Low Voltage DC controlling 120 AC, with Arduino

I'm looking for a type of device I can hook my arduino (micro-controller) to that will control a set of lights that require 120VAC. Basically I will be making a light organ, where the arduino will be ...
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2answers
114 views

DC Supply and Battery in parallel

Hey everyone I'm working on a project where I want to be able to power a thin mini-itx motherboard two different ways. Here is what I'm trying to do: 19V battery will be connected to a relay which ...
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1answer
62 views

Inrush Current Limiter for microPC

I'm looking at powering an embedded board PC using a 12V PSU and I'm having some trouble due to inrush current. The board draws 5A for about 1ms on startup and unfortunately this trips my PSU's ...
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1answer
60 views

AC to DC Filter Confirmation

Of the circuit I need to know the name of and what it is; my guess is, is it an AC to DC current converter? Is anyone able to confirm or deny? What does it act as when its all formed together? ...
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91 views

0-12V Adjustable Home Made DC Source not working [closed]

I have a home made dc source that is made a few years ago. Solders at the back of the board are very bad so I can not track the connections very good. But it's circuit diagram is very similar to the ...
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1answer
53 views

Using one circuit to switch another [closed]

I have 2 circuits. Circuit A is actually my android phone, for which I've written an app to send PWM signal through audio jack, voltage ~250mV. Circuit B is combination of 2 IR led and 2 AA cells. ...
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210 views

How to convert 6V AC to 5V DC

I'm looking to convert 6v AC (.5A) to 5v DC for use in charging a phone via USB. idealy a relatively inexpensive pre existing solution would be perfect, but I've been unable to find anything like that ...
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1answer
55 views

difference between a DC motor and gear motor [closed]

Isnt DC motor the same as gear motor? Because what is the use of dc motor without gears?
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1answer
104 views

Thermography difference between AC current wire and DC current wire?

Is there thermographic difference between AC current flowing wire and DC current flowing wire? And thermogramic differences for drift velocities?
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1answer
131 views

conduction current vs displacement current across capacitor [duplicate]

Kindly help me understand the difference between conduction current and displacement current. Quick searches explain that displacement current is associated with changing electric field, frankly ...
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1answer
96 views

Control of electric actuators

I'm new to this forum and I am trying to find a solution to control three small electric linear actuators I have made for my rc controlled model aircraft, they have mini 6 volt geared brushed dc ...
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1answer
104 views

How can I decrease a DC voltage without a resistor [duplicate]

I would like to light up a 2 W LED with a 3.7 V power source in the most efficient way possible. The Vf of the LED is 2.4 V. Is there any way I can reduce the voltage to 2.4 V from 3.7 V without using ...
2
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2answers
116 views

DC Brushless Motor For Electric Rover

I'm an industrial designer, and am working on building a small electronic rover, however I've been doing some research and I feel a little bit lost in terms of what motor is best for me, The device ...
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2answers
148 views

Step down 20V DC to 9V DC

What would be the best way to convert 20V DC to 9V DC? Can I use a simple potential divider network and regulate the output? If not, then what's the harm in it? I intend to use the output to power my ...
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2answers
143 views

Result of constant current through DC motor under different loads

I've done some research on brushless DC motor and have a few questions what would happen when a constant current is sent to a DC motor. From my understanding, the current is directly related to the ...