All Questions
21 questions
1
vote
3
answers
80
views
Converting ATX PSU to bench power supply
I'm posting this question just out of curiosity and also I know that you guys are expert in this electrical stuff building projects. I used to watch electrical circuits building videos in youtube in ...
- 11
1
vote
1
answer
77
views
Is it safe to remove this LED from that motherboard? [closed]
So, I've bought this SATA case from internet but it has a really bright light on it and annoys me. I don't haver any kind of tool to manage any electronic component, and neither have electrical tape ...
- 13
1
vote
1
answer
108
views
60Ω resistor in series with inductor with 80 Ω reactance, connected to 100V. How to calculate the impedance?
I do not have the frequency so I'm stuck. Which formula can I use to get frequency? And can I then, after getting frequency, substitute it into XL= 2πfL to get inductance or should I manipulate this ...
1
vote
1
answer
718
views
Calculate current flowing through each of the resistors in the following circuit: [closed]
I'm not sure how to go about this, but the answers are below
- 13
0
votes
2
answers
278
views
How to find a missing resistor?
This seems to be a really simple question. I'm not really sure where I went wrong in my solution. Please forgive me if this seems irritatingly simple, I've only just started learning about electric ...
1
vote
1
answer
291
views
How to simplify this complex DC circuit?
I find it very hard to simplify this circuit. Currently practicing for my removal exam and this was one of the problems I failed on one of my previous exams.
Especially the middle part makes me so ...
1
vote
2
answers
868
views
If the total resistance of the circuit is 5 Ω, determine the value of R3
So far I have answered question 1a and parts of b. This is my step by step process:
1a) P=IV
P = V/R x V
P = 20/10 x 20
P = 40 W
b) RT = 5, R1 = 10, R2 = 5; R3 = ?
let R3 = x
RT = 5+10+x
5+10+x = 5
...
- 147
2
votes
1
answer
178
views
Appropriate circuit for activating relays
I am trying to use two G5V-2-DC5 relays to switch four wires at the same time between two different outputs. All signals are 5 V. I've gotten this to work fine with a simple physical switch but want ...
- 151
5
votes
4
answers
1k
views
Averaging thermistor readings
I have 9 thermistors arranged in a grid, and I want to average the readings from these thermistors without code (that is, average them in a circuit rather than reading all the values into a ...
0
votes
3
answers
168
views
Help a beginner understand if a design is correct
I'm fairly familiar with Ohm's law and I did some calculations I'd like experienced engineers to confirm if it is correct or point where I made a mistake
Here's the idea
I want to power a self-made ...
- 103
3
votes
2
answers
839
views
Math behind pull-up resistors
I have a question about the the math behind of pull-up resistors and how they work. I don't have any experience in the Electric Engineering field so it's probably a basic question.
I saw many ...
- 41
2
votes
1
answer
155
views
Beginner circuit multimeter reads strange current
I have constructed the following very simple circuit.
I would like to measure the current running through the circuit with my multimeter. I break the circuit as follows and connect the red lead to ...
- 289
0
votes
2
answers
106
views
Unable to understand parallel resisitors
In the circuit attached in the image,I am unable to understand why R1,R2,R3,R4,R5 are not in parallel even though different current flows through them, any help would be appreciated
- 103
0
votes
1
answer
125
views
How can I calculate resistance from A to C and from A to B in this circuit?
I've got this circuit, and what I need to do is calculate the equivalent resistance from point A to point C. I've noticed these three resistors are connected in series, but how can I calculate the ...
- 21
0
votes
1
answer
146
views
How to combine two resistors in a circuit reduction
I'm new to electrical engineering so I've been watching MIT's Open Course Ware videos on Circuits and Electronics. In one of the lectures, the professor discusses the different methods to use in order ...
- 160
2
votes
3
answers
711
views
Do the resistors affect every component of the circuit?
I've noticed something strange in the circuits schemes I saw in a book.
Let's say that there is an LED and it's anode is connected to a 5V power source, and it's cathode is connected to ground.
...
- 231
0
votes
2
answers
98
views
Thévenin's theorem exercise, resistances
I've some problem identifying the \$R_{th}\$
simulate this circuit – Schematic created using CircuitLab
Removing the load and short circuiting the Voltage source we get :
simulate this ...
user201599
2
votes
1
answer
3k
views
RL circuit: How to determine the equivalent resistance of the circuit?
So I'm working on an RL circuit and the solution is stated to be that R1 and R3 are in series, but I didn't think that was the case because they don't have the same current through them. Given ...
0
votes
2
answers
289
views
What resistor to choose for circuit? [duplicate]
I'm not good at physics, but I'm trying to make a lantern. So I have an LED with this characteristics:
N = 3 Watt
I = 0.7 Ampere
U = 3.4-3.6 Volt
So I connect it to 6V battery, but need ~3.5 V. ...
- 103
3
votes
2
answers
5k
views
Find equivalent resistance at terminals a-b and c-d in the given circuit
I tried delta-wye transformation, which hasn't worked for me. Plus, I don't understand how to solve for two different pair of terminals, all problems before this had only one pair of terminals.
- 33
2
votes
6
answers
4k
views
Single LED connected in parallel to conducting wire does not light up
LED connected in series to resistor. All is well.
This doesn't work.
Neither does this.
This would be the schematic diagram.
simulate this circuit – Schematic created using CircuitLab
Why ...
- 123