# 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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### Why is the efficiency of a half wave rectifier equal to 40.6% and not 50%?

I'm trying to derive the efficiency of a half-wave rectifier using the definition for efficiency, $$\eta = \frac{\text{output power}}{\text{input power}}$$ And I also know that P = V_\text{rms} \...
311 views

### Where do I find good IV curves?

I bought a couple components for a quick project and like to know all of the math behind the voltages / current / resistance before I hook stuff up. For example, I bought multiple vibration motors off ...
125 views

### BIG Question about reading voltage with Ohms law and resistors [closed]

UPDATE: I have removed unimportant parts of my question to focus more on the topic I care about most, and to make it easier for answerers to understand my question. I have a question regarding ...
53 views

### Replace zener diode of 14v with two in series of 6.8v in power supply board of kenwood kr9940-9040 receiver board shorted

I am trying to repair a Kenwood quad receiver KR9940. This receiver has been given to me, hoping that I could give it a new life. It didn't power on, after first inspection I found a group of four ...
29 views

### Reroute Bluetooth speaker power

I have a Blaupunkt Bluetooth soundbar where the USB 5V cable is broken (the plug is indefinitely broken no repair possible.) My thought was to remove the 3.7V battery and use the cable to solder my 3....
332 views

### How important is the gate threshold voltage on a MOSFET

I am using several MOSFETs (STP16NF06 datasheet here) controlled by a shift register (74HC595 datasheet here) which is controlled by a microcontoller. The spec sheet says the gate threshold voltage is ...
88 views

### Is it possible to power an AC light bulb with DC voltage, if not then why?

I have a GreenLux E27 7W light bulb (AC 100-240V, 60 Hz) and tried to get a minimal light output from it by connecting ~2.40V 2 series connected AAA batteries. The bulb consumed ~60 mV (voltage ...
37 views

### Is it safe to power a 12V/2A WIFI router with the Molex 4-pin power connectors? [closed]

I have a SATA cable with a hard drive plugged in, And it has an extra 4 pins, I want to know if it's safe to power my router with it, I have already done it yesterday and everything seemed fine (...
34 views

### Solar power AC DC power conversion [closed]

I am getting quote for solar power. Two quotes say I need approximate a 6400 kW system. One said I needed 5760 kW system. When I asked why the difference, this was the reply. "The 5760 is not ...
131 views

### Is 5.5V safe for USB storage devices?

I have a USB-A 3.0 hub with ten ports. I've owned it for about 2 years now without any issues, until recently. About a couple of months ago I had a flash drive plugged into one of the ports on the hub ...
303 views

### Solar panel voltage drops when connected with load

I have a 100 watt solar panel with the specifications: Optimum operating voltage = 18.1 V Optimum operating current = 5.52 A Voc = 22.1 V Isc = 5.86 A. I connected this solar panel directly to a 100 ...
60 views

### Reading a negative and positive voltage through Arduino

Currently struggling with a problem due to my limited electrical engineering experience (1 first year course). I'm working on a project for central locking in the toolbox on my ute. The actuators ...
59 views

### Glitches in inductor current waveform

I am using this DC-DC buck converter. Schematics : Buck converter specifications : Input voltage - 18V to 32V Switching frequency - 300kHz Output voltage 9V Load current - 0mA to 200mA maximum. ...
46 views

### How to test a SMPS output?

Can we test output voltage and current of a 12V 30A DC switching power supply without any electric consumer (DC motor, LED strip, etc.)?
130 views

### Current and voltage [closed]

Suppose a 100W load works on 100V with 1A current. Can the same load work on 1V and 100A current flowing through it? (Not considering circuit breakers).
127 views

### Should negative and positive wires be of same length?

Do positive and negative wires need to be of same length all the time for a circuit to run smoothly? Of course same gauge but only different lengths. What would be its effect on the system if we say ...
42 views

### Workflow to test the quality of XLR microphone cables, and have a quantitative measure of this quality

I have more than 10 XLR microphone cables from different manufacturers (some of them quite cheap, some of them more expensive), and as I often do recordings (with condenser microphones) of music / ...
72 views

### Level shifter circuit for bipolar battery

I am using a 9 volt bipolar battery and I want to have an output of 1.6V for the ADC. What would a level shifter circuit look like for that? Do you have a better suggestion I can look into?
22 views

### Solar cell input for LTspice

I am trying to send a solar input into the LT8390 in LTspice. I am having trouble finding example circuits in LTspice that I can implement. Any direction or LTspice model files would be very helpful.
55 views

### Voltage multiplier not working

Why are both the voltmeters in the circuit showing the same. The blue one should have triple the voltage. What's wrong in my circuit?
33 views

### Is it harmful to touch only one point in a 200V circuit

Consider an LED setup where several modules are connected in series so their forward voltages (~20V each) add up to something around 200V. The setup is driven by a Mean Well HLG-480-C2100 driver. Now ...
21 views

### Unable to convert ultrasonic sensor 5V echo to 3.3V using TXS0108E 8 Channel Logic Level Converter Bi-Directional

I'm trying to use an ultrasonic sensor with a Raspberry Pi. The ultrasonic sensor's echo is 5V, but the Raspberry Pi's GPIO pins can only handle 3.3V inputs. I ended up getting an 8 channel logic ...
24 views

### Can a voltage higher than 5V be applied to the 28BYJ-48 (5V) stepper motor?

I want to automate my roller blinds by using an ESP (NodeMCU) and I was thinking of using a stepper motor. I had a 28BYJ-48(5V) stepper motor laying around with the ULN2003 driver it came with. ...
96 views

### Why are my LED string lights not working with an adapter?

I have a string of led lights that runs on two 3V batteries. When I measure the voltage on my multimeter it comes to about 6V as expected. I would like to use an adapter to avoid using batteries, so ...
61 views

### How to calculate the conduction losses diodes in each stage

how I can calculate the power losses for each step in The voltage multiplier (3 steps). I work in low voltage and power so some milliwatt losses are important in my system how I can calculate the ...
36 views

### Why didn't the IGBT's output voltage change?

I have a lab experiment and we are trying to make IGBTs switch. Here is our experiment: In first situation, our values like that: 10kHz, 10V pulse Vcc = 15V Frequency=10k And with this setup, I can ...
62 views

### Role of the output capacitor in buck converter in terms of frequency

I am using this DC-DC buck converter - buck converter. Schematics : Buck Converter Specifications : Input Voltage - 18V to 32V Switching Frequency - 300kHz Output Voltage 9V Load Current - 0mA to ...
48 views

### Oscilloscope probe coupling [duplicate]

I am using this buck converter. Schematic: Buck Converter Specifications : Input Voltage - 18V to 32V Switching Frequency - 300kHz Output Voltage 9V Load Current - 0mA to 200mA Maximum. When ...
50 views

### DC-DC buck converter low input voltage behavior

I am using this DC-DC buck converter. Schematics : Buck Converter Specifications : Input Voltage - 18V to 32V Switching Frequency - 300kHz Output Voltage 9V Load Current - 0mA to 200mA Maximum. I ...
33 views

### LT3663-5 with 5V and 3.3V output, can RTN be connected to common ground on circuit board?

I'm making an automotive circuit where both 5V and 3.3V is needed. I'm planning to use LT3663-5 and 1761ES5-3.3 to create those voltages. Now my question is, whether it is safe to connect RTN on 3v3 ...
28 views

### Control Circuitry in the Buck Converter Design

In this question, the last line of the accepted answer states that - That's why the text suggests using 1/5 or 1/10 of the switching frequency as an upper limit in terms of how fast you should design ...
29 views

### Variable capacitor in LTSPICE

I am trying to simulate variable capacitor in LTSpice. I have gone trough solution for variable capacitor with respect to voltage. But I want to change it with respect to relative permittivity. Any ...
38 views

### How to determine if level shifting is necessary between a 1.8V device (ICM-20948) and a 3.3V device (Arduino Nano 33 BLE)?

Background I'm having trouble determining the requirements for interfacing between the ICM-20948 and the Arduino Nano 33 BLE. The biggest issue for me is that there is a detailed datasheet on the ...
49 views

### Converter stability - bode plot

I referred this YouTube video for buck converter loop stability. In the image we can see that the gain of the control loop we are talking about is Vout / Vin. Vout and Vin are both measured across ...
87 views

### Using pull down resistor?

I have made an application with 3 Omron IR LED Photo sensors. This sensor can't be bought anymore, but here is the datasheet. I used a transformer 230 AC - 24 AC. Due to induction? the sensor output ...
71 views

### Simplest circuit for several hundred volts from 5v

I am trying to make a simple camera flash circuit for a project, but I am really having a hard time. I can't seem to find a simple circuit anywhere. It doesn't need to maintain the high voltage under ...
41 views

### MCP73871 Low Charge Current

I am trying to make some GameBoys use rechargeable LiPo batteries. I wanted to utilize a circuit that would allow me to play and charge at the same time and so I settled on the MCP73871. https://ww1....
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### Is it ok to supply 24 volt from the power supply with output 24 v 10 Amps to sensor which current & Voltage consumption (max) is 12-30V 35mA [duplicate]

Is it ok to supply 24 volts from the power supply with output 24 v 10 Amps to my sensor which voltage supply range+Vs is 12-30 V and current consumption (max) is 35mA, will current output from the ...
45 views

### How to find Thevenin equivalent of this circuit? Dependent current source

How to find the Thevenin equivalent circuit as seen from terminal a-b. I found out the value of Zth with ease but I'm not able to find the value of Vth. I tried using both nodal and mesh analysis and ...
59 views

### How to convert a -75mV signal into a +5V scaled signal?

I want to measure the current output from a 100A 12V alternator. The signal input format required by the PLC controller is 0 to +5V DC. To derive the base signal I have bought a DC shunt 75mV @ 100A. ...
52 views

### how to create voltage difference between two pins in IC

I have to create a voltage difference between two pins A and B of RS485 such that A-B < +0.2v what are my options to achieve this? is there any low cost break board for this? or any circuit ...
44 views

### Find total resistance using LTspice

How can I calculate the total resistance of resistors combination between points a and b ? I have already designed the circuit and added a 1 A current source between a and b. For dependent current ...
47 views

### Design of circuit and soldering onto veroboard

I'm new to electronics and I'm required to solder the circuit (2nd picture) onto a veroboard. I am however having trouble in designing it, with reference to the 1st picture, the left side of the ...
68 views

### When running two devices in parallel is the amperage always split exactly 50/50?

I have a AC to DC adaptor that outputs 12V 3A. This came with a USB HDD dock which has two slots. I want to splice a 12V fan into the wire in parallel so they are both powered by the same wall plug. ...
34 views

### What is the order of power intake across a GPU's power connectors?

On an Nvidia/EVGA 3080/3090 FTW3 GPU, there are three 8-pin PCIe power connectors. How does the "ordering" of power draw work across its 3x power ports (+ its PCIe slot)? For example, if a ...
28 views

So, i built a custom cooling pad for my laptop. Built in battery, 3d-printed case, etc. And the fan that i used is a basic 80mm case fan rated only at 12v. I want to run faster so i thought: how about ...
70 views

### Component for current and voltage amplification

I have a first current-generating circuit that produces an adjustable source/sink current (between + 10 mA and - 10 mA) with an output voltage range of Ā± 10 V. I want to amplify this current by a ...
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### I'm making a small refrigerator with a Peltier module but I can't find a heatsink. Will it work if I only use thermal paste and don't use a heatsink?

I'm making a small refrigerator with a Peltier module but I can't find a heatsink. Will it work if I only use thermal paste and don't use a heatsink? Can I use a 9 volt battery for a 12 volt module?
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### kcl and kvl what is the difference

I am very confused in the terms of what is the actual difference between kcl and kvl? I don't want to have a question on a test and not know where to apply kcl and where to apply kvl? Please help and ...