Questions tagged [basic]
Fundamentals of electricity, electronics, components, or theory
509
questions
0
votes
1answer
46 views
How does the flux density act on the conductor in the slot of a rotor?
Following picture shows north pole, airgap, rotor.
The conductors are placed in the slots.
It seems almost all the flux density is passing through the low reluctance rotor metal part.
Not much flux is ...
0
votes
1answer
39 views
How does the speed stay fixed when the resistance of conductor is 0?
My textbook has the following example of hypothetical linear motor.
A current carrying conductor is placed in a magnetic field.
The conductor is attached to a variable load(pulley+weight).
How it ...
-3
votes
1answer
94 views
Is my interpretation of voltage, amperes and ohms correct? [closed]
This is probably a very common question, but I feel most metaphors are somewhat simplified and therefore lack accuracy and
I think that makes me unable to fully understand them, but I've looked at it ...
0
votes
2answers
36 views
Why is dynamic power in this simulation with rectangular input voltage wrong?
The following circuit models the output of an inverter (voltage magnitude is 1V).
simulate this circuit – Schematic created using CircuitLab
The dynamic power should be independent of R1 and ...
0
votes
4answers
99 views
Physical circuit not drawing as much current as my calculations show
I've created the circuit below and have calculated the following values:
R' (equivalent resistance of entire circuit) = 1 / ((1/470) + (1/470) + (1/470)) = 157 ohms
I1 = VBattery / R1' = 6V / 157 ...
1
vote
1answer
58 views
What is the current induced in a wire connected to an ideal transformer using Faraday's law?
Imagine an ideal transformer interfacing an ideal current source with a ramp function \$i_1(t)=a t\$ connected to the primary winding and a resistor \$R\$ connected to the second winding. We want to ...
0
votes
1answer
48 views
Controlling 0-5V from 0-3.3V PWM pin and 5V power
What I have is I think a standard problem in home electronics but I can't wrap my head around it. I'd like to control an IKEA light chain from an ESP32 board. The chain is basically a set of LED ...
0
votes
2answers
106 views
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.
-1
votes
1answer
75 views
Parallel resistors connected only on one side?
In this diagram,
with four different resistors, in the lower circuit, we know that the voltage across all resistors is the same, and the currents are different. With the formula 1/Rn = 1/R1 + 1/R2 + ...
0
votes
2answers
80 views
What difference does it make if we touch an electrical appliance with wet hands? [duplicate]
This perhaps looks like 8th grade question. I have two different scenarios:
I am handling an electrical appliance with dry hands.
I am handling an electrical appliance with wet hands.
It is often ...
0
votes
2answers
56 views
Coil generator in practice
I am trying to create something like gyroball. Which features LED lights, so the faster the spinning, the more light LEDs emit. This seems like a simple scenario of a coil generator.
As an experiment, ...
0
votes
3answers
71 views
Clarification: the role of resistance in producing heat / light (e.g. incandescent lightbulb)
I'm reading Code: The Hidden Language of Computer Software to get a better understanding of what makes a computer work. Early on there is some elementary explanation of what electricity is, and how we ...
0
votes
1answer
43 views
Calculating current -- Thevenin?
Can someone please remind me how to solve this very basic calculation?
I've got a Wye configuration of resistors and am giving DC values 1V, 2V, and 4V to points A, B, and C respectively. I want to ...
1
vote
0answers
84 views
PNP- NPN light flasher
I understand that
R1 and R2 make a voltage divider.
initially Q1 is not conductive, so is Q2?
initially C1 acts as short circuit, so flashes the light L1 for a moment?
Please correct me if wrong.
...
-2
votes
1answer
109 views
Big confusion about the very fundamentals of circuit analysis
First, let's call IR3 the current flowing from A to B, IR4 the current flowing from B to C, IR5 the current flowing from C to (-V2).
What's the proof that IR3>0, IR4>0 and IR5>0?
I know this ...
1
vote
1answer
156 views
Help understanding a simple amplifier circuit using a single transistor
I'm reading Electronics for Dummies. So far it's great for a complete beginner, however, I've come to a chapter about transistors and either I've missed something or there's a sudden jump in ...
0
votes
0answers
57 views
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 ...
0
votes
0answers
39 views
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'...
0
votes
2answers
251 views
Output composite video (PAL) signal from FPGA DAC, totally lost in the analog domain
I'd like to start generating (and perhaps also capturing) composite video (PAL) signals from a digital source, eg. FPGA. However, while my digital logic/programming skills are covered, I'm lacking a ...
0
votes
1answer
139 views
Simulation not working well in Proteus 8.12
I'm not understanding Proteus or something I'm doing wrong, and it's really basic,
I put a 9v Battery, a Red Led, simple circuit and a 10k resistance, so the led shouldn't turn on right?
Well, is ...
1
vote
3answers
166 views
Does a floating load on a transformer have no voltage difference with ground?
I think I know the answer, but I'm unsure. I'm studying for my FE, and in the practice exam is the following question:
An ideal transformer connects a 120-V, 60-Hz voltage source to a load. One ...
0
votes
2answers
59 views
Basic RL curcuit problem
So I had an exam in basic electronics, which I passed but lost a lot of points on one seemingly easy task.
"Through the coil is passing a current equal to \$i_L=200\sin(10^5 t + 210°)\$. If R=5 ...
0
votes
2answers
59 views
Am I overthinking this simple power supply connection?
I want to connect a 12V fan and a motorcontroller to this generic ac to 12v dc power supply. The motorcontroller is pulling around 25 amps, and the fan about 1.
I'm just wondering, should i add a ...
0
votes
2answers
202 views
How to find current through inductor when connected in series with an ideal diode?
Please help me with this simple circuit, which is creating lots of confusion due to different results from theoretical calculation and SPICE simulation.
Ques: In this circuit switch is closed for time ...
0
votes
3answers
115 views
Resistors in series to increase maximum Voltage
Do the values of resistors matter when I want to use them in series to increase the maximum voltage they can handle?
So can I just use a 1 megohm resistor for example that's rated for 200 V and then ...
0
votes
1answer
106 views
Controlling a motorized ball valve and appliance with a float switch(es)
I am trying to create some redundancies for a small commercial ice maker to prevent there from ever being a flood in my garage. The ice melts from the ice bin (which holds around 80lbs of ice) ...
0
votes
1answer
221 views
Undervoltage lockout
I would like to do a simple undervolatge lockout. I thought a BJT as a switch like this:
In normal conditions I would have 30V (and -30 and the othre rail) and 25 mA to 50 mA. These power rails will ...
0
votes
1answer
66 views
Power Supply stopped working after soldering
I am new to electronic circuits.
I built a basic led circuit on a breadboard to test everything out.It worked as in pictures,but the connections were not stable because the holes were very large.I ...
2
votes
2answers
398 views
How to get negative voltage?
There's a bunch of posts about this, but they're all for very specific scenarios. I'm a newbit, and some components, like op amps, require both a positive, and negative voltage.
But how do you get ...
0
votes
3answers
99 views
Why is the resistance of parallel circuits lower than either of the individual parts
I am watching this tutorial, and topic of parallel circuits came up. In the below image, the combined resistance is 60Ω, which is less than either of its parts (150Ω and 100Ω).
I understand how the ...
0
votes
3answers
464 views
Voltage of capacitors after long time (RC Circuit)
I'm currently taking a course in electromagnetism, and I got stuck with this problem:
The Problem:
All of the resistors and capacitors have the same values, R and C respectively. The circuit is ...
0
votes
2answers
94 views
I'm trying to make a clock pulse generator but when I run the simulation nothing happens
I am new to using circuit/breadboard simulation apps. When I run the simulation nothings happens. Here is the original schematic.
Edit: I'm using 74HC00.
Also I learned how to use Virtual Breadboard ...
0
votes
1answer
109 views
Why can't KVL be applied here?
I was asked to find the Is current
I applied KVL in that loop but my ans is wrong.
what concept is wrong on my approach?Why kvl cant be applied on that loop please explain
0
votes
2answers
99 views
ADC is giving fault codes when I touch thermistor attached to it
I am working on writing a control program for my pellet smoker. I am having an issue with the meat thermometer that came with the smoker.
I have a MAXIM 31865 ADC that is connected to a Raspberry Pi. ...
1
vote
4answers
126 views
How to modify the supply voltage requirement in a circuit?
I am a beginner in Electronics; I am learning the basics and am trying to take up circuitry as a hobby! My query is regarding power supply requirement for any circuit.
Take, for example, a circuit to ...
3
votes
1answer
48 views
Thermal circuit for shared heatsink
I am following this video from EEV blog where he talks about calculating heatsinks and I noticed that he does not talk about multiple components sharing a single heatsink. I have lurked around the ...
0
votes
2answers
52 views
low-cost transmitter and receiver, no MCU involved hopefully
a newbie on electronics here.
I would like to create a simple RF kit. on transmitter side, only 1 button. on receiver side, if a valid code is received, a relay activates to provide 12VDC to a load.
i ...
0
votes
1answer
55 views
Would a DPDT switch work to turn either one or both devices in this circuit?
I'm doing a replication of vehicle hi/low beam switch in my "lab" and I'm not sure what's the right type of switch for it. It has to have a dedicated on/off switch (the one on the bench ...
0
votes
3answers
264 views
How to lower wattage of circuit
I want to power a computer fan from a 12v motorcycle battery.
Disregarding the motorcycle battery being 12.6 volts (not charging), lets say that it's a regulated constant voltage source of 12 volts.
...
0
votes
0answers
39 views
What is nominal SNR in Massive MIMO?
I have read a couple papers that mention nominal SNR in Massive MIMO. In the places where I have seen it, it says it is the SNR of the User when M = K = 1. This means that it is the SNR when the the ...
1
vote
2answers
315 views
Working of bipolar junction transistor with electron flow
I faced a lot of problems in understanding BJT. I am going to share what works for me.
Suppose we take an NPN as the transistor in our case.
The emitter base region is forward biased, so electrons ...
0
votes
2answers
78 views
On off switch with 2xLED
I'm trying to connect an old/possibly broken switch to a light from a 12V battery (very good first question isn't it?). The switch is meant to light Green when ON mode and Red in OFF mode.
The schema (...
0
votes
2answers
53 views
Why is my voltmeter output incorrect
So I'm completely new to electrical design. I thought I'd try out the most basic experiment I could think of. Here I hooked up two AA batteries to a breadboard along with a 10 K resistor. When I ...
0
votes
2answers
117 views
Will Kirchoff's voltage law work in a vacuum
Kirchoff's voltage rule tells us that the sum of voltages around a closed loop in a circuit will equal zero.
If a battery sits on a table, using KVL and treating air as matter with high resistance ...
0
votes
1answer
36 views
resistor combination circuit
simulate this circuit – Schematic created using CircuitLab
This is probably a very stupid question. I am new to electrical engineering in general, I was working with NOT transistor gates in ...
0
votes
1answer
103 views
Multisim Multimeter showing blank reading (--------)
I am trying to build a simple circuit to back up some hand calculations that I am completing for a project. However I am unable to get a reading on the Multisim multimeter. I have changed the ...
0
votes
3answers
265 views
Why does the impedance of a parallel RLC circuit approach infinity at resonance?
Pretty new to this stuff so apologies if I get some words wrong.
In the book I'm reading they described a parallel circuit with a resistor capacitor and an inductor powered by a current source. They ...
3
votes
2answers
119 views
Why does pin numbering and placement (in general) appears to be done so haphazardly to the uninformed person (me)?
Be it an ESP development board, an IC controller, even an LED segment number itself, pin placement never seems to follow a logic when it comes to actual numbering, or function. I can't find a simple ...
3
votes
1answer
148 views
Filter w/ seemingly higher output voltage than input?
I'm working on a simple LC filter as part of an AM radio project. I was intending to use a ferrite antenna (modeled roughly by the voltage source in series w/ inductor which is then connected to a ...
6
votes
4answers
401 views
Simple power on delay for 3.4v-5v serial device being powered by 5volt VCC
What I am trying to do
I am trying to build the most simple as possible circuit to give a 3.4v-5v serial device a 1-2 second power on delay from the embedded Linux device running at 5v that it is ...