Questions tagged [basic]
Fundamentals of electricity, electronics, components, or theory
570
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Calculating for Load Resistance given a T network in between the source and the load
Problem: Calculate the value of load resistance (Rl) for which maximum transfer occurs.
Attempt: What I know is that for the maximum transfer to occur, the load resistance must be equal to the source ...
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2
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788
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Figuring out if an led strip/matrix has a short or not with a multimeter
I am relatively new to electrical work, mostly stay on the software side of things. I recently soldered header pins onto a few led matrixes I have. They are 3 wire leds (power, data, ground). I'm ...
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1
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634
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Working out what happens to the brightness of a bulb in a simple circuit
I have been going through some past questions for my exam that is coming up this summer. I have come across this question which I originally deemed to be easy however the more I have looked over it ...
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3
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638
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How to make the output of a transistor the same as the input?
I'm new to circuits in general but have a basic understanding of it. However, it seems I can't wrap my head around the following issue:
(I'm using Tinkercad Circuits for trying out different ...
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1
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N Mosfet basics
Can somebody explain to me why this circuit will not work?
It might be that IRF3205 isn't a great choice for an Arduino but it works for Adam Welch on youtube so it should be possible. Tried it even ...
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2
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Fan not working on motherboard even if same voltage works with batteries [closed]
First of all I want to mention that I have no knowledge electrical field, so please forgive me if I will not be explicitly enough or I lack some terms, but I know no one with knowledge about ...
0
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1
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975
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Can a short circuit damage nearby devices? [closed]
This happened yesterday and left me scratching my head.
We had a badly built power extension cord in our office. Inside it has 3 wires - live, zero and ground (hope I got the terminology right). When ...
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I need the explanation on a DMM instruction manual
It's HIOKI DT4211 digital MM
In Electrical Characteristics section it states:
Rated power voltage: 1.5 v DC x2, use LR6 AA Alkaline battery 2x 1.5v
But then...
in Accuracy Table section, it states:
...
user154285
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3
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Digital Rotary Encoder -- Broken? Or am I misunderstanding how it works?
I apologize if this seems like a fundamental question, but I feel like I'm missing a fundamental understanding about digital rotary encoders, because none of my basic encoders are working as expected.
...
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2
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Basic circuit analysis - phase shifting
For the part of the circuit of sinusoidal circuit given below, the following data is given (effective values): $$E=10V,I_g=2\sqrt 3 A,I_2=2A.$$
Impedance of conductor is $$Z_C=5\Omega.$$
Current Ig ...
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3
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2k
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Switching between two parts of a circuit using basic components
I'm designing a circuit in which i need to temporarily switch between different branches of it. I know that it can be done using a relay with coil etc, but I'm wondering if there is a way to do it ...
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531
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Wire 5 vibration motors on one switch
I am trying to run five vibration motors rated at 3.7 volts each on one switch. The power will come from a 12V, 40 Amp relay on my Jeep (SPOD). How can I wire the motors all together to turn on at one ...
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RMS of a complex waveform
For a complex waveform as follows:
One can find the squared rms of the complete waveform by finding rms of individual components and then square multiplying it with the corresponding duty cycle.
$$...
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144
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Is electric charge a state variable since derivative of charge flow is defined as current?
\$ i=\frac{dq}{dt} \$
Is 'q' a state variable in general?
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Electro-static potential of a capacitor during a transient?
How would I calculate the electro-static potential for this simple circuit during the transient (during the time the capacitor charges)? Do I just use Ohm's law?
simulate this circuit – ...
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High power IR transmitter circuit for ESP8266
Currently I am using this IR transmitter circuit for an ESP8266:
It works, the reception is not bad, but I need a little bit higher power to control my AC unit. The AC unit is ca. 10 meter away from ...
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when a capacitors is being charging from a battery is battery discharging?
I'm studying yet.
Is a battery discharging when capacitor connected to it is charging?
Please explain how does it work!
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2
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973
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Understanding voltage and current - is there voltage without current flow?
I'm trying to increase my knowledge of electric circuits and their major components. My current understanding is very basic, which will explain why my question may seem laughable to most people on ...
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333
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Unable to make a pot work correctly
I have a board I salvaged from a joystick that uses potentiometers to measure the location of the arms. On the PCB a edge pin and the center pin are wired together. I would like to connect the pots to ...
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1
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200
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Oscilloscope training resources
I would like to learn to use an oscilloscope properly. I used them a few times at school, but that was a long time ago and I've forgotten most of what I learned about their use.
I'm now working with ...
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When do I need a resistor during LED flashing? [duplicate]
My goal is to flash a few white LED in serial using 9V battery.
Here are the specifications of this LED.
As I saw the Forward Voltage is 3.4V, but what does it really mean?
Can't I plug this LED ...
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1
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74
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questions about open circuit, pull up resistor and MOSFET selection
Please let me ask 3 questions about meaning of open circuit, calculation of pull up resistor value and selection of MOSFET.
I'm trying to understand how to use the TPS3808G33 reset IC and the ...
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215
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Kirchhoff law in Electronics Workbench
I have a task to check Kirchhoff laws in this circuit.
If I understand everything right, I3 + I2 should be equal to I1, but it isn't. What's wrong?
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How a solar charge controller can work on both 12 volt and 24 volt
Please excuse me for my silly question, I have basic understanding of electrical circuits.
I came across a solar charge controller which was rated for both 12 v and 24 v. My understanding is that ...
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Having trouble with light activated circuit.
R1 = 10K 1/4W Resistor
R2 = Photoresistor (any type)
R3 = 2M2 1/4W Resistor
R4 = 1M 1/4W Resistor
C1= 10µF 25V Electrolytic Capacitor
C2 = 100nF 63V Polyester Capacitor
D1 = 1N4148 75V 150mA ...
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1
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99
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Headphones with dual jack, reduced volume
I recently built a pair of headphones and added an audio jack input to both the cans, for convenience of connecting.
That would also serve another purpose of letting my girlfriend hear the same music ...
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1
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115
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Converting digital signal to analog
What is simplest way to convert digital signal 1 0 0 1 0 0 1 0 0 (i.e. 1/3 of time its ON and 2/3 of time its off) into sinusoidal signal of same frequency, which can vary from 3 KHz to 6 MHz?
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Small UPS for bluetooth audio device
I've got a bluetooth audio receiver in my car and am finding it annoying that it turns off immediately after the ignition is turned off. For example if we're stopped for a while I prefer to turn the ...
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Calculating the gauge of wire required for the secondary in a Tesla Coil
I am looking to build a small Tesla Coil at home with limited supplies. I am reasonably confident (well.. as confident as a biologist can be!) with my calculations so far, however I have hit a mental ...
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2
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250
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LEDs, Voltage and Resistors
I noticed that a Christmas Light uses 20 LEDs in series parallel, operated by 2 AA batteries (3V) without a resistor.
I thought you always need a resistor?
Would it be possible to run them on 5V (...
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470
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Photo transistor in parallel
I'm a beginner and trying to figure out how this circuit works (its a simple circuit that glows an LED when dark) :
https://www.youtube.com/watch?v=eIGWWKThprI&list=UUhtY6O8Ahw2cz05PS2GhUbg#t=65
...
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Working of RC Phase shift Oscillator?
Figure show a RC phase shift oscillator using Op-Amp with gain 5(Vo/Vi).
My assumption : Circuit is generating a sine wave with a peak to peak voltage of 10v.
Consider positive maximum point (+5V) ...
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250
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How can two steel balls with same amount of charge be at different voltages?
Maybe this is the most fundamental question, but still it eludes me.
Is it possible for two balls each containing 1 Coulomb of charge be at different voltage levels, say 1V and 2V relative to a ...
user50716
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Plain English explanation of the Space-time Code Block by Alamouti
I checked about the Space-time code block online, but all of the explanations are either short or too simple, or too mathematical and complex
Could anyone here provide an explanation of what Space-...
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487
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Generating a desired pulse train in Xilinx ISE software
Need some help with VHDL and FPGA since I am new to it.
I have a Virtex-4 FPGA and I wish to generate a binary pulse train of 16 pulses from FPGA using VHDL programming. My desired pulse train will ...
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1
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759
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SSR function con control panel
I'm new in electronics and would like to build an electric brewery with an electronic control panel. I found on www.instructables.com one control panel and is described as in following image.
Could ...
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469
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Experimental calculation of dc motor resistance
I am trying to calculate resistance of DC motor experimentally.
I have measured voltage and current for different voltages applied (from -5V to 5 V). Motor shaft is blocked.
And the question is why ...
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1
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710
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How can I trigger a photography strobe from a iPhone LED flash?
I would like to trigger a photography/studio strobe flash based on the flash of an iPhone camera's LED flash. I'm picturing a device that I could attach to the back of the iPhone temporarily when I ...
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1
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KVL equivalent versions
How do the first two statements (quoted below) logically correct when the third is viewed as voltage drops are only across resistors and the voltage rises are only across voltage sources? Where is the ...
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2
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Is passive sign convention the exact oposite of active sign convention?
I'm currently studying the fundamentals of electrical circuits. For my studies, I'm using the book "Fundamentals of Electric Circuits 5th ed."
In the introduction chapter, section 1.5 Power ...
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0
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52
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Help On Dual Amplifier Design
I am pretty new to electronics and so far, have been teaching myself and designing things with the help of the internet. I made and designed a class-AB amplifier circuit that drives two 8-ohm speakers ...
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1
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84
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Choose the RLoad resistor for zener diode
I need to calculate the Rload resistor range for the operation in this case:
I know that many times to calculate the Rseries but now he is given,
how does my teacher expect me to calculate the RL?
...
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If there is a ground potential (V = 0), is there a ground current?
Can current be defined with respect to some "ground current"? If so, how?
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Smartifying simple USB lamp with ESP8266 / Voltage regulation 3.3 V <-> 5 V
I am a complete beginner and my electrical knowledge back from school is basically non-existent anymore.
I have discovered the ESPHome project and am amazed by its simplicity, so I wanted to turn a ...
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0
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79
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Avoiding power drop in LED strip lights
I am wiring a van and will be putting in ~25-30 feet of LED (RGB+W) strip lighting. My main power supply is a 300 Ah, 12 V battery. I am familiar with LED strips, dividing and connecting them, but I ...
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Representation of any signal using unit signal
I was introduced to the unit step signal and told that we can write any discontinuous signal in terms of the unit step signal to omit the discontinuity from the mathematical expression.
So if we are ...
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1
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206
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What happens if we give a negative trigger pulse before a monostable multivibrator reaches it's stable state
Monostable Multivibrator using Op Amp, from this link,
Obviously there is a certain amount of time that the capacitor takes to charge again from -Vcc*β to VD (0.7v) and therefore during this period a ...
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2
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159
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Why does this circuit flash the two LEDs even without a 555 timer?
Can you please help understanding how this circuit is flashing the two LEDs? I know about transistors, capacitors, and resistors functionality, but can't get how this works without a 555 timer.
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Can I syphon power from a USB-C smartphone and still charge the phone?
I'm designing a device (simple 5V LED) that will be powered by a smartphone (via the USB C socket). I am struggling with allowing the phone to be charged at the same time via the same connection.
Is ...
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non-ideal op amp closed-loop gain derivation
How do I derive an expression for v_o / v_s?
This answer fills some gaps but it doesn't tell me how they came up with the expression for V^- (corresponding to -v_d in my notation).
ETA: here's what I'...
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