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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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32 views

Combining AC and DC components in same Spectra/Molex Microfit connector

I am making a control unit. It will interfaced with AC devices like fan, pump, light along with one DC device, namely, a Solenoid lock. All the devices will be placed outside of the control unit. I ...
8
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1answer
200 views

What are the purposes of these capacitors?

My son and I took apart a small electronic toy and were wanting to see the inside. Once we cracked it open I saw this circuit and couldn't figure out what each piece did. I think I understand the ...
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42 views

Measuring AC output of variac with DC voltmeter

I have variac (Uin=230V, Uout=0-250V, Imax=5A), where I would like to measure voltage on output on a digital voltmeter. Since I have problems finding digital AC voltmeter 0-300VAC (most of them ...
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57 views

Physical connection of AC and DC voltage sources in series

in many circuits (Amplifiers, Filters etc) at the input terminal I saw a sinusoidal voltage together with a DC term, i.e. a voltage like v(t) = sin(wt) + 1 [V]. We may imagine that this signal is ...
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67 views

how to demux 100V to 300V DC signal into 8 channels?

I need to 8 channels of 100Vdc to 300vdc, load current 10mA to 80mA. my idea is to use a step transformer to step up dc 5v 1A source to 300Vdc 50mA (typical application). low voltage side of the ...
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45 views

Send an AC signal from a DC device

I was able to read a 18VAC signal from the old-school door bell with a voltage divider to my 3.3VDC ESP controller. Nice. Now, I wish to send a 18VAC signal (for 3 seconds) to open the door with that ...
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1answer
51 views

What is the maximum current limit of this motor?

I am confused about the maximum current limit of this DC Motor. Rated Power is given as 220W and Rate voltage is given as 24VDC. According to this maximum current should be 9.166A. But 2.5Amax is also ...
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2answers
453 views

Reverse Voltage?

Sorry, I searched but could not find (or maybe understand) and exact answer to my question. I am a carpenter, not an Electrical Engineer. My passion is building things (almost anything) and ...
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2answers
34 views

Low-RPM motor with limited torque for a newbie [closed]

I'm developing ... an electric yarn winder for medieval distaff. The aim is to spin wool on the spool, keeping certain tension level. I mean, when the tension is too strong, the motor should not break ...
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0answers
26 views

12v DC motor info ?? Schematics ???? Fix? (DRCP5030LA) [closed]

Any one familiar with this motor (DRCP5030LA) I pulled it off a refrigerator it's for the evaporation fan . Except iv never seen a motor like this one I was playing with some magnets with it and it ...
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3answers
539 views

Simplest way to reduce voltage from ~48v to ~36v

(I'm very much a beginner with electronics, so I apologise in advance) I’m trying to use a 48v battery on my 36v ebike controller. The controller itself can deal with the higher voltage, but it has ...
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53 views

DC Power Supply maximum current

let's consider a DC power supply of 5V with for instance 1A of maximum output current (i.e. its maximum output power if 5W). Let's connect a load R = 1 Ohm. Ideally a voltage source of 5V will give ...
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50 views

how is this transformer working with DC? [duplicate]

As I was going through the SMPS circuits online I came across this circuit: I searched and learned that the transformer steps down or step up only AC power supplies and then converted to DC using ...
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1answer
106 views

Question about fingering

I have designed a circuit in Cadence Virtuoso. As a first step, I used all the transistors without fingers (i.e. each transistor is a single transistor). Once the circuit satisfied all the ...
2
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2answers
149 views

Would 5.5 x 2.1 mm male plug work inside a 5.5 x 2.5 mm female jack for DC power?

General Question I am wondering, is it possible to use a 5.5 x 2.1 mm male plug inside a 5.5 x 2.5 mm jack for transferring 12 Vdc? My thoughts are just that it may just be a tight fit on the inner ...
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1answer
48 views

Some help with buzzer schematic and reducing power troughput

I have a water tank with a built in simple 'float switch'. It acts like any other switch. Last year I tried connecting it to a buzzer so that I would know when the tank would be empty. This burnt out ...
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1answer
31 views

Wiring 4+ 12v led ring switches from one 12v supply

I am new to electronics and general electronic circuits. I have 4+ led ring switches (from here: follow link) The website says that the rating of the switch contacts is 5A 250VAC with an ...
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20 views

security camera power by solar regulator [duplicate]

i have a solar panel with regulator to run a a light as well as charge a battery. i want to add a security camera which uses a power supply of 9 volt dc and 600ma. instead of using an inverter and ...
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2answers
56 views

Reducing 16.5VDC battery output to the range of 13.8VDC +- 15% without introducing noise for 15 Amp load

The title pretty much says it all. The (up to) 15A load is a ham radio, which is the reason for the 'no noise' constraint. Maybe a tiny bit of noise is OK? I don't know how I could tell. To save you ...
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2answers
42 views

Trying to measure start current of a DC motor

I have an 12V DV electric winch I am attempting to power with a power supply. I am only pulling about 150 lbs and I want to know what the... Start up current Running current The winch starts and ...
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1answer
64 views

Unknown equation in the SPICE resistor model

I was looking for simple resistor spice model, and came across this: ...
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2answers
96 views

Why a double fuse is used in some applications?

In some DC applications in an isolated system (i.e. no grounding), sometimes two fuses are used: one is positioned on the positive (Vcc) line while the other is located on the negative (return path or ...
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1answer
57 views

What is a sufficient way to ground my 2 layer low frequency PCB inside a housing?

I'm designing a simple PCB for GPS signal control. The frequency is below 5Hz, supply voltage is 9V and converted to 5V. This print will be screwed in a plastic housing with four M3 mounting holes at ...
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1answer
24 views

Increase in SMPS output voltage with RF amplifier as a load

I am trying to use an SMPS of 50 V output ,16 A current capacity from meanwell make for powering one of the RF amplifier operating at 13.56 MHz. The amplifier is evaluation module of MRF300AN. The ...
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11 views

Build 9V powerbank from a generic USB-C PD (or QC3) powerbank [duplicate]

I need to use a powerbank with device with these requirements: 9V, 500ma. New USB-C with PD feature can deliver higher voltages than standard 5V and 9V (upt to 2A) is one of these. As far as I know ...
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1answer
77 views

What tool do I need for measuring DC power consumption of device over a period of time?

I have a device that's being battery powered and I would like to measure the power consumption over a longer period of time (~24Hours). I want to read both the voltage of my battery and the current ...
1
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1answer
147 views

How does such an USB step-up 5V-12V work? [closed]

I just bought a cheap USB 5V to 12V step up converter: Surprisingly, it works very well. There is few place for electronic components (maybe in the USB connector?), how can we do a 5V to 12V ...
0
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2answers
96 views

Is 1 Hz equal to 1 rotation of a motor shaft?

I'm rather new to the world of electronics but I have been trying to find the frequency of a DC motor. I've found that 1 hz is equal to 1 revolution per second, but does that refer to shaft rotation ...
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1answer
60 views

Integrator with DC control gain

I am analyzing the integrator circuit and I can't get from which equation can I get the frequency where there is the intersection with x axis - 1/C*R1 ? Thanks! source
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0answers
43 views

Why are many 9V DC wall adapter power supply measured as 12-14V by a multimeter? [duplicate]

I have tried with many (working) 230V - 9V DC wall adapter power supply (of different brands, some of them coming with an electronic Yamaha device, etc.): they all show a higher voltage when ...
0
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1answer
84 views

Confusion regarding a 12V DC motor's RPM

I have a 550 DC motor of 12V, 45W and 10K RPM installed on a wheel, which is not causing the wheel to turn fast enough when the motor is connected to a 12V battery. I replaced the motor with an older ...
1
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1answer
57 views

How do I know to choose a first order filter vs a second order filter?

I have a DC signal coming off of a battery. The Arduino is reading the voltage. The issue is that the voltage signal contains a lot of noise (120hz frequency). I am planning on building a first order ...
5
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2answers
1k views

1kV DC Circuit - Insulation on ground wire?

If I have a 1kV DC circuit, does the ground wire need to be rated for the full 1000V? The circuit is pretty simple, two wires from a power supply to a resistive load.
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2answers
98 views

Running an electric motor beyond its ratings

I ordered a 36V 500W brushed DC motor but unfortunately a 24V one came. I'm faced with the dilemma of returning it and waiting for a month before getting a refund, then ordering a new one and waiting ...
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2answers
103 views

I'm trying to learn how to make these circuits but have no clue if I'm on the right track? [closed]

I've recently been doing some online tasks but I am really struggling to understand how build this circuit in multisim. I am also struggling to calculate the values listed in 2. and have tried to find ...
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2answers
64 views

24V DC Power supply on the cheap?

I have an application where I need a 24V DC Power source at approximately 5 Amps (so approx 120 Watts). I've also got a shed load of old computers which all have 12V power supplies rated at up to ...
2
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2answers
71 views

Brushed motor with shorted contacts can still rotate

From what I read here and on the internet I understood that shorting or adding a big load to the contacts of a DC motor will make it very hard to turn as a generator. I have a 500W brushed DC motor ...
0
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1answer
29 views

Suppressing Transient Voltages - DC circuit

I have a DC circuit with a 24-26v voltage source (from a battery). The secondary function of the circuit consists of 2x step down converters, 1x to 5v and 1x to 12v. The step down converters are ...
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2answers
50 views

Help with my design: How can I add these voltages?

I have to design a circuit that simulates a voltage spike on a dc supply rail. The circuit has a button that, when pressed, generates a short pulse of controllable height (controlled by pot). The ...
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2answers
55 views

AC/DC Converters in Series with the Same AC Source

Would it be safe to connect two identical AC/DC converters in series if they share the same AC source? My concern is that the negative DC output is grounded somewhere in the converters causing the ...
0
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1answer
53 views

Cascading/multiple voltage dividers

Could someone explain the voltage readings on the following "oscilloscopes" of the simulated schematics below: (I understand the concept of a voltage divider but it seems something less ...
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2answers
96 views

Can I use this DPDT relay with this circuit? If so, which wires connect to what terminals?

I'm following this tutorial to wire an automatic chicken coop door. The DPDT relay they're using is different to my relay so I'm finding it difficult to understand which wires connect to where. I'm ...
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1answer
72 views

Adding DC voltages of PSU [closed]

I need to add two voltages together that share a common ground (power supply from computer). I tried using bridge rectifiers and Op-Amps.
0
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2answers
74 views

Motor freeweeling and regenerative brаking FOR DUMMIES

The project I'm working on is an electrically powered vehicle. I have found this fairly simple circuit to control my motor's speed. What I understand is that when the transistor is closed the battery ...
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2answers
83 views

Controlling DC fan with Mosfet PWM

I am trying to control a 12V DC fan with PWM using an IRFZ44N MOSFET. However somehow the fan is not turning on and off when the gate is pulled to either 0V or 5V (on the power supply). And it is ...
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1answer
81 views

Is it possible to patch together a DC system with these random materials? [closed]

I have a small collection of random batteries and solar panels, plus two charge controllers. I am hoping to build a system which can charge devices like phone, tablet, portable power banks, etc. (...
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0answers
47 views

Protection Devices in DC ciruits

I am putting together a design for a custom Electrical panel. The panel consists of mainly DC powered components (Sensors, Controllers). Components are to be mechanically positioned using a DIN rail. ...
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2answers
108 views

Diagram shows four wires coming from my two wire power supply, what am I missing?

Completely new to electronics and I’m trying to follow a blog post to wire up a linear actuator to a dpdt relay and photocell. I’m stuck, because the diagram I’m following is showing a total of 4 ...
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2answers
63 views

Meaning of firing angle in the context of a DC input supply

I've learnt the meaning of firing angle only in the case when the input supply is AC. As shown below So what does firing angle of 60,120,180 degrees mean when the input supply is DC? Like in a six ...
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2answers
68 views

What DC Power Supply Do I Need To Get For This Device?

I recently bought a small 3 to 1 HDMI Amplifier Switcher. It can work without power adapter only if the 3 HDMI inputs are connected and supplying current. I want to operate it with only 2 input which ...