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Questions tagged [voltage]

Voltage, otherwise known as electrical potential difference (denoted ∆V and measured in volts) is the difference in electric potential between two points (adapted from Wikipedia). Voltage can be constant (DC) or varying (AC).

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12V DC voltage drop for second switch 10 meters away

I have a ground floor main door lock operated by a solenoid (12W, 12 V), the switch (push button) of which is located at first floor, the power to this switch is given by an AC to DC(12V) adaptor - ...
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41 views

What would cause a voltage rail to be held low without measuring a short circuit?

I have a circuit that provides power (1.8VD) to an FPGA and some ADCs. I have seen in the past where damage (ESD, EOS, etc) occurs to one of the ADCs. This causes a short from 1.8VD to GND internal to ...
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51 views

Suitable NMOS with 3.3V gate voltage to switch 12V 500mA

I've got a circuit board with a D2PAK NMOS pad that I need to find a mosfet that will work with a raspberry pi's 3.3V GPIO. This is the current one I'm using and it isn't working well. https://www....
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what limits the maximum voltage of this optocoupler (6N137)?

In the datasheet it is stated that the maximum VCC voltage is +5.5V.(https://www.vishay.com/docs/84732/6n137.pdf) Because ive been told to question everything (and i have enought of them to kill one ...
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How can I increase the AMPs in a transformer less power supply

I am very new to electronics and trying to do something which I am not much aware of yet. I have a NodeMCU (based on esp8266) for which I need power supply of 5V and it required I guess more then ...
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56 views

Random Noise Voltage

I have a signal I am interested in obtaining power from. The best way to describe the signal is that it is random. In the graph, the voltage fluctuates from negative to positive with an RMS of 0.5 ...
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115 views

Battery failing. Oscilloscope?

The question is - is there an inexpensive oscilloscope I can use to measure DC voltage and current to see why my battery pack is failing to power a DSLR? In order to take long time lapse photos with ...
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87 views

Sharing a USB keyboard between two PCs on a button flip

The PCB for the task would comprise of a USB connector, two sets of 4 PTH for the two USB cables (one set towards PC 1, the other towards PC 2), shared GND and TX and a DPDT switch for separating the ...
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Powering a 3 Phase 230VAC Motor with 28 12V Batteries wired in Series

Mechanical Engineering student here. I'm a part of a senior project team that trying to run a 40 HP 230 VAC three phase motor with a 40 HP VFD for a hydraulic pump. Our plan is to wire 28 Lead Acid ...
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52 views

5 V and Ground Reverse direction

I have a circuit drawing like below image. I need to replace a connector, but when I checked the connection is different compare to the original drawing. (New connection indicated by red color) 1) ...
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222 views

What types of mechanical switches are appropriate for a 200 V DC 20 mA circuit

I have looked at many switches, most recently I considered snap action switches (micro switches). What I prefer to use is a PCB mounted switch, but I cannot find any that can tolerate the V DC ratings ...
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Way to power a monitor that requires 12 V 2.5 amps with a PC USB port [closed]

I am looking to see if there is a way to power a monitor like this: (https://www.amazon.com/gp/product/B07774L6TT/ref=ask_ql_qh_dp_hza) over one (or two) of the PC's USB ports, so theoretically it ...
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Can I run DC voltage through RJ45 Connector with Magnetics?

I am designing a PoE (Power over Ethernet) application. My question is can I run 48V DC Voltage through a standard RJ45 Jack WITH Magnetics? or do I need one WITHOUT magnetics? I am planning to use ...
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1answer
3k views

How much time does it take for a switch to go from on to off?

The equation for the voltage across an inductor is v = L di/dt. When a switch changes the circuit from closed to open, it changes the current very quickly. My question is how would one know exactly ...
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40 views

What does this bidirectional TVS diode do

This is a schematic for a crude taser design ive been studying. From what i can tell when the switch is on the relay turns on and off continuously, which charges up the LC circuit in which the ...
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Calculating voltage loss using impedance of a system

simulate this circuit – Schematic created using CircuitLab So I'm trying to figure out the Total impedance Z of a system with a capacitor in series with a resistor and inductor, where the ...
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1answer
22 views

Maximum Vin on load switch ICs

I'm trying to determine whether the absolute maximum rating for Vin on load switch ICs applies for when the switch is both open and closed. When the switch is closed, it makes absolute sense to me ...
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1answer
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How much load for a given source? [closed]

Given a micro controller with X Volt DC power supply, what is an easy way/rule of thumb to determine how much devices I can connect to the controller (assuming each device requires Y Volt DC)?
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Linear Regulator Operation

I have a linear regulator with three pins. It's identifier is LM7805. I've taken a look at it's datasheet and it looks unlike linear regulators I've encountered. Is the the op amp circuit included in ...
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2answers
119 views

Torque and speed control of a DC motor

I'm new to electronics and this is my first post so please be patient with me. Introduction I am required to design a rehabilitative exoskeleton-like knee-brace to assist sit to stand, I have faced ...
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1answer
73 views

USB ground wire — Where does the voltage go?

I am trying to figure out where exactly the current of the ground wire of a USB 2.0 cable goes? I am referring to the pin number 4. I know that normally, the current flowing on the ground wire ...
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1answer
27 views

Simulating absolute value circuit in TINA-TI

I am looking to build an absolute value circuit using a pair of op-amps, hopefully using a single supply and would like to simulate my design using TINA-TI. The ultimate aim is to measure the voltage ...
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1answer
84 views

LT3751 voltage never increases

I am using LT3751 for the first time, tried alot but no luck need help. I am using the chip in regulation mode and following the circuit given in datasheet on page number 26 with title "High Voltage ...
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3answers
72 views

TTL IC logic high output doesn't reach high enough voltage

I've been having a problem trying to build a breadboard circuit. The problem being, that some IC high outputs doesn't reach a high enough voltage, staying around ~2V. That is not sufficient for a ...
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41 views

Voltage and amperage requirements for resistance heating of glass

I am planning to introduce electric heating/boosting in my glass melting furnace. The present temperature of the glass is around 1200 deg C and I need to raise it up to 1300 deg C. I am trying to get ...
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Why a CFL lights up when I touch it?

When there is a very low voltage (AC), even for a compact fluorescent lamp (CFL), it glows very dim (orangish in color) at the beginning of the glass but when I hold the glass just for a second, it ...
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68 views

0-20mA to voltage conversion. Is this circuit OK?

Is this circuit OK, in your opinion?
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2answers
117 views

6 volt drop to 1.2 volts

I am working on a circuit for my deer feeder. I now have a 6 volt power source running the spinner on the feeder and it has a 6 volts solar panel recharging the battery. I made a new circuit control ...
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1answer
54 views

Measuring Output Ripple voltage in Scope

I have a DC-DC converter which converts 16V to 23V. I have an output E-Cap at the end of the converter. I need to measure the ripple voltage at the E-Cap. I am using a 300MHz scope. I connect my ...
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3answers
60 views

would like to verify a filter design I need to make for a backup camera in my truck

I am installing a backup camera in my truck. I am getting some source of electrical "noise" in the electrical system in my truck and its not allowing the backup camera to operate. Let me explain a ...
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1answer
98 views

Voltage drop - Diode reverse biased

Can you please help me with this exercise? In each circuit, calculate the current flowing through the 10kΩ resistor and calculate the voltage drop across the germanium diode. Please assume that a ...
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1answer
33 views

Calculating the voltage difference between a switching pin out and a constant Vout

Sorry to trouble you all with a similar question. But this is a different question altogether regarding calculation of voltage difference. I am using NCV3063 IC. According to my design of the boost ...
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How to trigger power bank to output 12V? [duplicate]

I have a power bank that can output 5V fast charge or, 5V 9V or 12V regular charge. https://www.banggood.com/JUWEI-QC2_03_0-Automatic-USB-Tester-Voltage-Ammeter-Quick-Charger-Power-Bank-Voltage-...
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Producing clean power with multiple switch mode power supplies

Thanks, I am new to using this site, I apologize for my vague post earlier. Here is a schematic I been working on. The project requirements are 5VDC, and 20VDC. The 5VDC is to power the ...
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2answers
57 views

Is there any design consideration to keep in mind when switching to higher capacity lithium batteries?

Long story short, had an RC drone with 3.7V ~1400maH lithium batteries and switched to 3.7V 2.2AH battery. But now the whole electronics cut-off when the throttle is pushed beyond mid-way (i.e. Higher ...
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Voltage Equation in Time Domain

When we describe a AC signal (voltage is this case) in time domain we use an equation something like this below: \$v(t) = V_m \mathrm{sin}(\omega 𝑡 + \phi)\$, where 𝜔 is the angular frequency of ...
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How can an electron have 0 electric potential after exiting a resistor but have current?

Unfortunately, I am not able to respond and ask a question on this specific post so I am going to ask a question based on the answers of the user "Transistor" in this post because I am still confused. ...
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5answers
169 views

Transformer Outputs Voltage High Above Expected Voltage

I have recently put together this circuit, which works basically as expected. Due to my lack of certain parts, however, I had to replace the 68 Ohm resistor with a 52 Ohm resistor, and the MOSFET I'...
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72 views

Finding the voltage across nodes A and B

I've tried solving it and have managed somehow to make out the answer but it isn't in a systematic way.
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1answer
56 views

Automatic Power Selection with MOSFET

I need a circuit which will automatically disconnect the battery from LOAD when ext. DC power is connected so that the battery won't get damaged. Theoretically a pair of diodes can solve this but ...
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2answers
2k views

Voltage Regulator Design Not Working

I have attempted to design a 12V to 3.3V switching regulator for my PCB that will draw 0.5A Max. The problem is that after assembling the components, the output voltage is the same as the input ...
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3answers
68 views

Does voltage limit current?

When I short the negative and positive wires on my DC lab power supply, at ~1V the supply shows it's max current output of 5A. but when I turn down the voltage, at some point the output ampere ...
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1answer
35 views

Check for live high voltage shielded three phase conductor

We would like to know if a shielded high voltage cable 8000V AC, 3 phases, is "live". Whether there is current flowing or not. Ideally we design a little device that's strapped around the cable (...
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1answer
22 views

How to combine 5V-powered ATmega16A and MAX44009? [duplicate]

I'm programming my ATmega16A through LPT port using uisp -dprog=bsd. Although ATmega16A supports \$V_{CC}=2.7\,\mathrm V\,..\,5.5\,\mathrm V\$, to make logical ...
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1answer
56 views

voltage drop - operating a solenoid after a logic gate and a LED

I have started meddling in circuitry, but I lack any sort of formal training. Subsequently I apologise for my ignorance. The circuit I have made (on paper) so far has a number of issues, but I want to ...
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142 views

As we go around the circuit, the total voltage drop must equal zero

I am studying an advanced mathematics textbook. One of the examples is within the context of an electrical circuit (a series circuit, I think). The example makes the following claim: As we go ...
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25 views

Battery voltage indicator using a RGB 5050 LED strip

I am looking to use a 5050 RGB LED strip to show either green, blue, and red depending on the battery I want two monitors voltage. If I take my LED strip and connect 12 volts to it and then ground one ...
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66 views

How can you change grid voltage in a vaccuum valve?

I understand in a valve the level of amplification is determined by changes in the voltage of the grid or in the anode, but how can you change the voltage of the grid? And can this be done dynamically,...
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2answers
72 views

~36 volts on Neutral <-> Ground

I'm trying to understand what is going on here - this is in a normal house linked to the grid (240 volts / 3 phase), nothing extra. On two sets of plugs (next to each other), I measure 36 volts ...
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55 views

How to compare power requirements for different control design approaches?

I am trying to fairly compare different control design approaches. As an example, below I present two similar but different techniques which are: Control system with state feedback Control system ...