Fundamentals of electricity, electronics, components, or theory

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2answers
36 views

Conditions for Thevenin and Norton non-existance

It's not clear to me when a Thevenin or Norton equivalent cannot be produced for a given linear circuit. Can anyone help me with a clear definition? Thanks!!
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1answer
52 views

Why Can't I get a Smooth Sine Curve in PSPICE

I am trying to simulate a Volume Control Circuit in PSPice Student Edition. I am unable to see a smooth sine curve at the output. Could you check my circuit. Find the Schematic below Thanks
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3answers
42 views

Voltage across Capacitor and Inductor with DC Voltage and Current source

As we know, capacitors and inductors are most important components in circuit design. I am just curious about how they will behave when connected across voltage or current source as per below image ...
0
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2answers
36 views

Understanding id-Ugs and id-Uds graph of a nMOSFET

I'm so sorry posting such a horrible-looking picture, but I really cannot found pictures similar to it online and/or in English! If you found one, please let me know and I'll replace it immediately! ...
0
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2answers
63 views

Ambient LED Project

I'm working on mounting LED strips to my entertainment set up and part of it involves mounting strips to the back of my TV. I want to power the LEDs via a USB port found on the back of my TV. I'm ...
1
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2answers
51 views

How does logisim differ from redstone and real life circuitry?

I recently developed an interest building circuitry systems. It started in Minecraft and then grew when I picked up a micro controller from Radio shack to build an RC car with. Obviously I'm most ...
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1answer
74 views

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 ...
-1
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3answers
77 views

DUO LED controlled by one MCU pin

I'm having trouble controlling red/green LED. I need to control it from my MCU with one pin. The pin can pull-up or pull-down and the LEDs can be with common cathode or anode. I'm flexible on that. ...
3
votes
1answer
74 views

Complex number \$e^{jk\pi} = (-1)^k\$

I know that \$e^{jk2\pi}\$ or \$e^{\mathrm{integer}}\$ will give you 1, but I can't find the proof for why \$e^{jk\pi} = (-1)^k\$. Can someone please explain how \$e^{jk\pi} = (-1)^k\$? Does it ...
0
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1answer
52 views

Sensing a touch of a metal

Assume there is a piece of metal. I would like to identify, with a microcontroller, if another metallic object is touching this piece. I want to apply this for a smart hook that "knows" if a ...
0
votes
1answer
93 views

Transistor delay switch equal to a SPDT Relay

I have a circuit I need the functionality of a SPDT switch that is flipped a couple of seconds after power is applied. It is just switching data lines on a USB port so there is no current being ...
0
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1answer
78 views

If this element is unidirectional or bidirectional ? (see the image)

Below the I-V characteristics of two elements .Is these elements are unidirectional or bidirectional ?
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1answer
32 views

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 ...
0
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2answers
60 views

Can a COTS FM Radio transmit?

This is probably a really silly question, but I still want to know... Given a standard off-the-shelf FM radio alarm clock, what is to stop it from transmitting radio waves when physical motion causes ...
0
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2answers
40 views

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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1answer
54 views

Is there a limit at the voltage you can apply to a transformer primary?

I have a 9v transformer but all it says is that, there is not info on the primary. The voltage supplied to my house is 120v. So, the transformer will just lower the voltage by a 0.075 factor, ...
12
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6answers
1k views

Why are crystal oscillators used in clocks instead of RLC circuits?

The timing of quartz clocks is regulated by a crystal oscillator. This crystal oscillator effectively forms an RLC circuit. If this is so, what properties does a crystal oscillator have that makes ...
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5answers
167 views

Why does a resistor reduce voltage if V=IR? [duplicate]

I'm sure this is a very simple question, but I have been confused about this topic for a while now. According to Ohm's law, resistance varies directly with voltage. This means that if resistance ...
0
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1answer
37 views

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 ...
1
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1answer
82 views

Power rating for opto-triac trigger circuit resistors

RHS will be using 220v 400watt bulb 2 simple questions 1- does the 360ohm resistors has to be of high watt too ? 2- all i can find is 5-10watt resistors, can i use them ? would they snub correctly ...
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1answer
122 views

Pull Up/Pull Down Resistor Confusion

I have googled the crap out of this but I can never find a good answer. In a circuit with a pull up resistor, why is the input pin fed current with a resistor? A pull down resistor circuit doesn't do ...
0
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2answers
71 views

Is a Van de Graaff generator a voltage or current source?

I'm currently studying basics of electrostatics and this question comes to me as any generator must be from either of the two types but which is the fact I'm not able to justify which. From its ...
2
votes
1answer
67 views

What are limitations of Kirchhoff laws in presence of A..C current.what are the bounds on its application in such case?

I'm not able to understand while Kirchhoff's laws seem to be based on very fundamental logic they are still not applicable in some cases. I tried to look for answer in text book but got no clear view. ...
5
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4answers
406 views

Understanding current, voltage and resistance

I'm still trying to wrap my head around current, voltage and resistance, and slowly I have the feeling that I start to get some things. Hence, I would like to describe my understanding so far and ask ...
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votes
3answers
92 views

Should HDL languages be taught before software languages? [closed]

I'm a Computer Engineering student and learned the basic sequential programming languages (C/assembly/Java) way before I was even introduced to HDLs. Thus, my whole programming logic was based upon ...
3
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3answers
301 views

Why does isolation transformer protect from shock?

Perhaps I can best explain the question with two examples: (1) there is PC powered directly from 230V mains (unprotected by RCD or similar), and there is fault in PC that causes line voltage to ...
3
votes
2answers
345 views

Is capacitor reactance [sometimes] defined with negative sign?

Wikipedia currently claims so but I've looked in 6 books via Google Books and it's not defined like that, i.e. it's just $$ X_c = \frac{1}{\omega C} = \frac{1}{2\pi f C} $$ Is Wikipedia full of ...
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1answer
50 views

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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votes
2answers
84 views

Voltage reduced when using NPN transistor

I'm currently trying to reverse the voltage at a DC motor ports, from 5V to -5V, to invert its rotation. I also want to be able to have 0V at theses ports. I have a micro-controller that is able to ...
0
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2answers
89 views

Why do LEDs need resistors and lamps do not in a series circuit [closed]

Obviously a basic question but unbelievably difficult to get an answer I understand that LEDs are diodes and that if you don't limit the voltage to a LED it will blow because it draws as much current ...
2
votes
1answer
27 views

How to determine total circuit voltage and individual component resistance for a series circuit

This is a question from someone who has just started to learn electronics. I'm a bit confused Lets say I have a series circuit with three lamps. Lamp 1 needs 1V, lamp 2 needs 2V and lamp3 needs 3V. I ...
0
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2answers
87 views

What is an n-by-n matrix in a series-parallel circuit?

I started reading a textbook about basic electronics and I reached a section about series-parallel circuits. Here is an example of a series-parallel circuit: simulate this circuit – ...
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4answers
80 views

How do logic gates operate? [closed]

I know what the major logic gates are, I know that each gives a different output depending on the input. However, that's all I've been able to find. Every time I look it up, its a list of gates and ...
0
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1answer
54 views

Explain trim pot for VU meter

I have the following schematic that is supposed to rectify the signal going to a VU meter and also trim it, so the user can adjust the position of "0dB". What I don't understand is why and how the ...
0
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3answers
86 views

How to improve this amplifier so I can get up to 5 Watt output in 8ohm load

This is Class A amplifier I trying to make up to 5 Watt output for 8 \$ \Omega \$ load. Is this amplifier circuit OK?t gives about 800 mW out on 8 \$ \Omega \$ load.
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0answers
45 views

What is the correct order and setup of AC coupling capacitor and line driver? [duplicate]

When I use an AC coupling cap along with a balance line driver, what is the correct setup? What happens when I omit the resistor in the following schematics? Is it neccessary? simulate this ...
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1answer
86 views

very basic basics [closed]

I just started studying but I've been having problems because my professor assumes that we know very basic things that we actually don't. So my questions are: What do I need exactly to have an ...
3
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5answers
1k views

High Current or High Voltage that damages components?

Very basic question here and I'm only looking for a generic over view, but is it a too high current or a too high voltage that will damage electronics? I assume it will depend on the component in ...
0
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2answers
166 views

Phase difference between voltage source's voltage and current

I tested a simple circuit with AC voltage source and, when I probed the source input for voltage and current, I was surprised to find that they were 180 degrees out of phase. I tested in the LTSpice ...
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2answers
96 views

How is amperage “soaked” out of the outlett?

I have some struggles understanding how amperage works. What I understand so far is that amps are the amount of electrons which get pushed by the voltage. But if I have an outlet with 230V~ which is ...
1
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2answers
116 views

Why does my current in parallel circuit not add up when I check using a multimeter?

I have a simple circuit 9v connected to 3K resistor coneected to a wire. On this wire, I have two LED's connected in parallel, both leading straight to ground. When I check insert my multimeter ...
1
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2answers
83 views

Simple Detect Physical Touch - If object is up against the sensor/object

Definition: Physical touch, meaning the touching of a physical object. Not objectively human in nature, just anything touching / covering the sensor or switch. The above line is included as every ...
0
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2answers
73 views

A simple apparatus to detect whether my ear touches a metal plate lying on the floor

For the sake of simplicity, I just want to create a simple apparatus that produces blinks when doing push-up exercises. However, in the future, I will probably combine this system with a digital ...
0
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3answers
104 views

Resistor power ratings

Fuses, circuit breakers, transistors, ect... are all rated in amps. Why are resistors rated in watts instead of amps? Does their breakdown/failure include more than just heat?
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1answer
67 views

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 ...
0
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1answer
85 views

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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2answers
132 views

Can capacitor charge to higher voltage than source provides?

Hi I played with some basic circuits in lushprojects.com simulator and came up with this one that surprised me - when the capacitor C1 is charged for the first time by pressing the SW1 switch the ...
1
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1answer
236 views

AVR switch best practice

After reading a lot of posts (here and on the web), I am a bit confused. All I want to do is to get the best practice of push button connection to AVR. I have 2 "sections" to my question. the first ...
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1answer
171 views

Basic transistor switch

I'm just an amatuer working with some electronics at home. I am trying to use an NPN transistor as a switch. 9v on the Emitter, 6v as the control on the Base to activate the switch, and I'm going to ...
0
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0answers
56 views

Solving the equation for Common Drain

So I've designed an all NMOS amplifier to further voltage amplify the 5V max output of an Opamp to 24V rails. I used a Common Source at the very end so I'll have a very low output Impedance. Of ...