The basic tag has no wiki summary.
6
votes
3answers
134 views
Transistor Toggle Not Working
I'm trying to learn about how transistors work. As a simple test I created the following circuit:
My idea is that when the second transistor will keep the first one active after I click the button ...
3
votes
3answers
141 views
How to electronically generate exponential and logarithmic functions
i mean, it is possible to generate with Op amps, or diodes, etc, to generate complex exponential and logarithmic functions, like one can create sinusoidal signals using a Wien bridge oscillator.
...
2
votes
1answer
130 views
Calculating current in a simple circuit
I am new to electronics and am trying to figure something out:
I have a source putting out 12.6V and an unknown current.
I know that I can calculate current by finding the voltage drop over a ...
3
votes
3answers
114 views
Controlling LED with microphone input
I know this is an extremely simple question, but I haven't been able to figure this out on my own. I'm trying to get an LED to get brighter as ambient sound rises. What I've come up with: use a ...
4
votes
1answer
225 views
Basic rules to calculate the equivalent resistance of a resistor circuit
I have a certain circuit only containing resistors of different values. There is one 'input' and one 'output' for the current. How do I calculate the equivalent resistance of the circuit? Are there ...
0
votes
3answers
110 views
Op amp design that gives \$V_{out} = -2 *V_{1} + 3*V_{2} - 3 V_{3}\$
I know that a regular summing amplifier does \$\ V_{out} = -(a*V1 + b*V2 + c*V3)\$ but how do I invert one of the gains?
3
votes
2answers
174 views
Grounding in circuit diagrams
Often I see in circuit diagrams that the circuit is connected to the ground:
I understand that this creates a reference for zero potential, but why does all of the current not simply flow right ...
3
votes
4answers
289 views
Early Effect, Ebers-Moll, Common Emitter Resistance, reverse alpha/beta and saturation current
Ive been reading Sedra/Smith's Micro Electronic Circuits book, and it has a lot of info which I like, however I dont know how much of it is actually practial and useful, for instance it talks about ...
1
vote
1answer
97 views
How to choose an external powersource with electronic logic [closed]
I am a n00b in electronics (software developer)
I have 2 batteries bat1, bat2 (1.5 volts) available to me. I can only use one battery in my circuit. Let's say that if the battery is put in a holder ...
-6
votes
2answers
99 views
(Need help ASAP!) Electric motor bike with BASIC Stamp [closed]
We're doing the project is to develop an electric motor bicycle to assist the bike rider going up steep hills. In our project, we modified a bike with combination of electric motor, goniometer sensor ...
1
vote
3answers
2k views
How does current flow through a voltage source?
Im going back to electricity 101 to understand several things Im missing. One of them is exactly how does current flow through a DC source.
Heres my understanding: A voltage source is one which has ...
3
votes
3answers
263 views
Fundamental question about circuits and grounding
I understand that voltage is relative and that the hot wire in house mains is a nominal \$\pm\$ 120v in reference to the neutral wire. I also believe the ground wire is connected to the neutral at the ...
0
votes
1answer
77 views
which battery will supply the load?
I have connected 14V supply terminal from alternator to 12V battery terminal and has taken the load across these terminals . But the load is operating still in 12V, and when measured across the ...
0
votes
2answers
143 views
Intro Circuits Class Inductor question
This is a question from my intro circuits class that I can't figure out the answer to:
Of course it's very simple, but I had a professor who was incomprehensible most of the time, and my textbook ...
2
votes
4answers
166 views
Overload protection for battery
My 6-year-old son has shown some interest in electronics, and I thought I'd get him some basic components (motors, LEDs, buzzers, etc) and let him experiment (using alligator clips and the like -- no ...
5
votes
2answers
364 views
Designing a cable tester
I need to check the integrity of 40+ custom cables. Each cable is meant to be the same, and is meant to have 19 ways.
I bought an enclosure, some mating connectors, some LEDS and a bunch of ...
6
votes
2answers
2k views
How to wire a GSM module to my alarm system
I have an alarm system that has been installed by an alarm dude ;)
I want to add a GSM module to the alarm system, so that I'm notified when the alarm is triggered. Before I purchase the module I ...
4
votes
3answers
190 views
Capacitor discharge and 1/2 terminal voltage sources
I understand that this is really basics of electronics, but I would really appreciate if somebody clearly explained following question.
So here is a small set of questions related to similar topic:
...
1
vote
3answers
482 views
Why voltage lags by 90° from magnetic flux?
I was not sure if I should write it here or on Physics board, but I will give a try.
As I understood current (generally emf) can be generated in a system by varying magnetic flux.
For example, let's ...
2
votes
1answer
197 views
Basic nature of electric current/voltage
I'm curious about electronic/electric. I just want some visual, easy to understand explanation/depiction about basic nature of electric current/voltage, relations between them, why electrons make a ...
3
votes
4answers
1k views
How can I learn electronics at home? [duplicate]
Possible Duplicate:
Learning about electronics
I am 40. I am an architect by profession. I am very interested in learning electronics.
I don't have time to go to college for an ...
3
votes
2answers
499 views
What's a good way to start learning how electronics and circuits work?
I literally already tried getting a degree in Electrical Engineering, and I hated it, and I switched to Computer Science.
But here's the thing-- I find circuits and electronics and electrical devices ...
2
votes
1answer
786 views
What is Normalized DC Current Gain (as oppossed to DC Current gain)?
I have a table that presents DC Current Gain for BC548B transistor:
and a graph that presents Normalized DC Current Gain:
Are those two things related? What does "normalized" mean? Why is the ...
6
votes
6answers
6k views
How electrons inside copper wire behave when source is ac or dc?
When a simple copper wire is connected to AC or DC, what actually happens to the electrons inside the wire?
I.e. What kind of path do they follow when they reach the end of the wire? If anyone can ...
2
votes
1answer
194 views
What is the impedance of this unusual (magnetically coupled) circuit?
Inductors X1 and X2 are magnetically coupled
M = 20 [Ohm]
X1 = 20 [Ohm]
X2 = 30 [Ohm]
I am not sure how to interpret short circuit. Is the circuit impedance given by the equation:
_Z = R1 + ...
2
votes
2answers
2k views
What is the voltage divider rule?
Can anyone explain what the voltage divider rule is? How has the author of this book used it for analyzing the Voltage Divider Bias circuit for transistors?
And can anyone explain how the two ...
3
votes
4answers
4k views
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 , ...
1
vote
2answers
544 views
Why is the Ampere the only SI fundamental unit for electricity?
According to wikipedia the only SI fundamental unit for Matters Electrickal is the ampere. Don't you at least need the ohm to derive anything? How would you make volts from only amps?
Perhaps I ...
-2
votes
2answers
658 views
Principal of Analog to digital converter(ADC) and Digital to analog converter(DAC)
Analog to digital converter is one that converts analog output form sensors to digital one what are basic principal of Analog to digital converter(ADC) and the opposite of one that takes digital input ...
5
votes
5answers
401 views
What are analog and digital signals?
I came across the concept of analog and digital signals in my data communication course. We studied that analog signals are continuous signals and teacher presented a diagram like the sine wave and ...
7
votes
2answers
4k views
How does an astable multivibrator LED blinking circuit work?
I am beginner to electronics. I come to know about oscillator using RC circuits (Capacitor charge and discharge and time constant tells the behavior of circuit).
Then I saw following circuit that ...
2
votes
4answers
567 views
Why we need to complete circuit
Why can't we light an LED with a single positive wire on the anode, leaving the cathode unconnected?
Let's suppose I connect a wire with a positive voltage to the anode of the LED. Now, I think, ...
2
votes
4answers
1k views
Low pass audio filter design
I want my Arduino project to listen to the ambient music and sync its light show output to the beat.
It seems that doing BPM detection properly is fiendishly difficult in software, but if your music ...
5
votes
5answers
1k views
What is an amp (and other such basic questions) in the simplest possible terms?
I understand that this is a really basic question, but, I've been unable to really understand electrical terminology for some reason. What exactly is an amp? How does it correspond to a watt?
And:
...
6
votes
4answers
621 views
Transistor with two voltage levels, Vb ≠ Vcc
Why is my transistor only driving 5V instead of 6V? How can I fix it?
I have a 6V, 25mA circuit running some LEDs. I can control them by connecting and disconnecting the positive terminal of ...
11
votes
4answers
3k views
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 ...
5
votes
2answers
1k views
FTDI Basic Breakout - 5V
Can this board be used to upload sketches to the Arduino. I tried by hooking the TX port on the FTDI Basic Breakout to RX port(Pin 2 on the Arduino) and RX port to pin 3 on the Arduino. But so far I ...
1
vote
1answer
266 views
