# 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).

420 questions
5k views

### Determining suitable wire gauge for LED-strips (voltage drop)

I am software engineer by trade and a novice in this field, please point out any mistakes in my assumptions and vocabulary regarding this topic. I am designing a lighting plan based around commonly ...
52 views

### Voltage increase by connecting Voltmeter

I've got this scheme. V1 and V2 are voltmeters without their own power supply. (V1 gets power from the measured circuit, V2 is powered separately, but in this case from the same power supply.) The ...
210 views

### Mistake in published paper about magnetic levitation?

As I was reading through this paper: Nonlinear Model & Controller Design for Magnetic Levitation System, I stumbled cross section 3.3 which I could not follow. Summarizing section 3.3 Non Linear ...
484 views

### Convert [-24V,24V] range analog signal to [0V,3.3V] range for ADC

I need to realize a circuit that converts an analog signal from [-24V,24V] to [0V,3.3V] before sending that signal to an ADC "MCP3208". I found the circuit in the picture below and it works perfectly ...
449 views

### Voltage Translator (74HC4050) Voltage Fluctuations

I have a simple circuit with a simple problem that I just can not fix. I have a 74HC4050D hooked up to an SD card. I have a 0.1uf on the 5V line and 2.2uf on the 3.3V line. Whenever a signal is sent ...
1k views

### PSpice VSIN frequency - how to set it in rad/s?

I know, that if I want to set FREQ, I need to set it in Hz, not in rad/s. I know, that 1 Hz = 2*pi rad/s, but how to do this in PSpice? What should I enter exactly? and btw. if I want to set VOFF (...
65 views

### Why the opposite of the passive sign convention is not the active sign convention?

Studying the fundamentals of circuit theory, I was reading the Wikipedia article on the Passive Sign Convention and found out about the Active Sign Convention (ASC). After searching many introductory ...
91 views

### Why do I have voltage on Collector and Emitter when NPN transistor turns on? How to get rid of it?

I have a 2N3904 NPN transistor. I'm feeding the base 5V. the transistor turns on just fine and it shorts the collector and emitter. However, when I turn my meter on volts, I read around 1- 1.5 volts ...
38 views

### Calculating equivalent resistance using loop analysis with no applied voltage

I have a bridge circuit that I am supposed to find an equivalent resistance between points K and P for using loop analysis. I am aware that a delta Y transformation is the much more direct route, ...
57 views

### 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 ...
72 views

### 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 ...
43 views

### Voltage drop on power bench supply for channel being off

If I measure voltage drop between terminals of my bench power supply (spec) I get -15 mV when channel output is turned off. Why it is not reading 0? I believe it's due to internal impedance of the ...
55 views

### How to go about finding the transfer function of a non-linear circuit?

Note: The concept of Transfer Function is only defined for linear time invariant systems. Nonlinear system models rather stick to time domain descriptions as nonlinear differential equations rather ...
49 views

### Off load voltage in npn transistor as a switch

There is transistor tutorial on sparkfun.com (https://learn.sparkfun.com/tutorials/transistors/all). I am wondering why there is 1.3 V drop depicted across the LED1 on the picture, since when the base ...
35 views

### Source voltage of circuit with diodes when output voltage is given

Tried solving this using KVL, and solving to get the currents for the different parts of the circuit, however got stuck when trying to compute the source voltage especially that I'm unsure if the ...
84 views

### Finding Current in Parallel RLC Circuit with 2 voltage sources?

I've spent sometime learning about step responses for series/parallel RLC circuits, but this problem takes things a step further, since C seems to be in parallel with a series combination of RL and a ...
41 views

### How do you calculate average absolute value of a sum of sin functions with different amplitudes and frequencies?

I cant seem to find the answer anywhere. I remember there was a simple formula for doing this but I dont have the book with it anymore. Finding where the function is positive and where is negative and ...
141 views

### RL Circuit Analysis with 2 sources, how to find current of resistor?

I've been tackling some problems related to natural and step responses for RL & RC circuits, but I think I've hit a major roadblock for this RL circuit. I'm trying to find the time constant and ...