Fundamentals of electricity, electronics, components, or theory
Questions tagged [basic]
551 questions
67
votes
8 answers
Can a circuit be powered from Earth with a return ground on Mars?
Could you use a hot wire (120v 60 hz) from earth and a copper rod inserted into another extraterrestial body (mars) to complete a circuit? If impedance wasn't something to worry about (pretend Mars is only a mile away or something).
I've asked this…
user2476549
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41
votes
10 answers
What is a Charge?
I'm a high school student. I love computers and electronics. Few weeks ago, I thought to build my own electronic gadget but, unfortunately I had not much knowledge in electronics. So, I decided to learn. After Googling here and there, I came across…
seek_learn_joy
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26
votes
9 answers
LED and lamp in series - why does the bulb not light?
My 6 year old son has just started experimenting with a Snap Circuits style kit and already we have a very basic question.
If we arrange an LED and lamp in parallel powered by batteries then both LED and lamp light up brightly.
However, if we…
Mark McLaren
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26
votes
6 answers
ATMega8: why do VCC and AVCC have to be connected?
I often read that it is good practice to connect VCC with AVCC. Even in the ATMega8 datasheet it says so:
AVCC is the supply voltage pin for the A/D Converter, Port C (3..0),
and ADC (7..6). It should be externally connected to VCC, even if the
…
Peter
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23
votes
9 answers
Why are electrons not pushed out from the conductor at an open circuit under the influence of a power source?
Frequently, electric current is compared with water flow. For example, if I make a hole in a water tank, water will flow till the tank pressure and the atmospheric not become equal or the tank becomes empty. Why does this not happen with…
user3131972
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20
votes
13 answers
Path for a child to learn electrical engineering
What are some paths for a child (7-year-old) to learn electrical engineering (in a safe way)?
I do not want to saturate (or frighten away) the child with lots of concepts, I want that my son learn playing with the basic and core of electrical…
moonw
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19
votes
6 answers
Do electrical devices "take what they need"
One concept of electronics I have a hard time understanding is if things like motors, actuators, solenoids etc. use as much power as they need or what you give them.
If a motor needs 12 volts and 500ma and I supply it with 12 volts and 3000ma will…
G Thompson
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17
votes
3 answers
What operation could cause the inductor or the capacitor to explode?
In really early days of electronic school, the teacher used to say something about not unplug power too quickly at an inductor or capacitor and we were used to slowly turn the voltage generator from a signal generator down to zero. Something about…
Fraïssé
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17
votes
2 answers
How does an astable multivibrator LED blinking circuit work?
I am a beginner in electronics. I come to know about the oscillator using RC circuits (capacitor charge and discharge and time constant tells the behavior of circuit).
Then I saw the following circuit that blinks 2 LEDs timely in sequence.
Will…
Zain
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16
votes
5 answers
How do I connect two identical batteries to increase the consumer lifetime?
If I've got a device that uses a single battery, and with that single battery, the device lasts an hour, and I want the device to last for two hours, I'm assuming I can wire two batteries up and it should work. But how? Do I want to double the…
Eric C.
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15
votes
3 answers
Basic operation of a bipolar junction transistor
I've tried really hard to understand the basic operational principle of a transistor. I've referred to many books and been to forums but have never got a convincing answer.
Here are the things I want to understand:
A transistor is similar to a…
JGalt
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14
votes
2 answers
When to use a 1/4 Watt resistor vs 1/2 Watt resistor
I have never understood the difference between 1/4 & 1/2 watt resistors, and in all of my EE lab courses I have always just used 1/4 Watt resistors. When does one use 1/2 Watt resistors and what is the difference between 1/4 & 1/2 Watt…
Adam
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13
votes
6 answers
How does an SR Latch get started
Noob question, but I'm not seeing how an SR latch such as the one in the image can "get started". If each input depends on the output from the other, how can there be two inputs to each gate to set the thing in motion?
In a rudimentary circuit…
Robin Andrews
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13
votes
5 answers
Why should a circuit be grounded?
Why should a transistor circuit be grounded? The way I understand it is that ground is an infinite supply of electrons and so it is equivalent to the negative terminal of a battery. But in this page , there is both a negative terminal and the…
Green Noob
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13
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5 answers
Why is capacitor a linear element?
Why is a capacitor a linear device?
One property for linearity is that the capacitance or some such parameter must not change with voltage or current. Is this enough to make a device linear?
A few sources say that the \$Q=CU\$ has a linear…
Bhuvanesh Narayanan
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