Tagged Questions
0
votes
0answers
27 views
Differential BJT Amplifier [closed]
I am trying to solve this assignment
Consider this schematic (the BJT's are in the effective area, with
$\beta=200$ so as to $i_e\approx i_c$).
Define the common and differential gains, ...
2
votes
1answer
56 views
How we approach RLC circult from RLGC model?
In the text, it introduces a practical model to investigate a transmission line (like BNC cable), it considers the transmission line has resistive $R$, inductance $L$, conductance $G$ and capacitance ...
1
vote
1answer
43 views
When does Thevenin's theorem not apply (modelling a power source with a ohmic internal resistance)
Most physics text books say that a power source can be modelled as an EMF with a internal resistance. This is also know as Thevenin's theorem or Norton's theorem. However I have read in some sources ...
-1
votes
1answer
81 views
Differentiating a sinusoid [closed]
http://i.stack.imgur.com/ndLgm.png
I don't see the how the author derived that $\frac { dv }{ dt } \leftrightarrow\overrightarrow { V } j\omega$.
0
votes
0answers
51 views
Transfer functions of active filters
I've been looking for some straightforward method or trick to obtain the transfer functions of active filters (like the Sallen-Key filter, the butterworth or Cauer topology etc...) since KCL or KVL ...
0
votes
1answer
71 views
Full wave rectification [duplicate]
In the construction of a full wave rectifier, why is there central tapping in the secondary winding of the power transformer? What's the pure reason behind it? If there was no central tapping, what ...
2
votes
2answers
93 views
Electronic filter
Can you explain, please, step-by-step how Electronic filter does work?
For example, high pass filter. I know It's a trivial things, but I can't get it completely. Don't bring me formula and etc... ...
0
votes
1answer
175 views
What is the role of center-tapping in a full wave rectifier?
Note: I have already tried googling. Although similar questions have been asked on different forums, I couldn't find a detailed explanation, which I could really understand.
Circuit diagram ...
0
votes
1answer
238 views
AC Circuit Theory Maximum Power Transfer
I am currently hitting a barrier with regards to the basics of this question.
A 50HZ supply is connected to various given impedance's, calculate the maximum power transfer.
Maximum power transfer I ...
0
votes
0answers
19 views
How are current and voltage out of phase in capacitive circuit? [duplicate]
Possible Duplicate:
Physical explanation for capacitive circuit
We say that in capacitive circuit, the voltage and current are out of phase. Current is 90 (degrees) ahead of voltage. What ...
3
votes
1answer
166 views
Explanation of the Graetz circuit
My knowledge of circuits is pretty rudimentary and I've never really understood circuits, so I'm having trouble with the concept of Graetz circuits:
When you register the voltage on the resistor R ...
0
votes
0answers
58 views
Explanation of NMOS processes
So, gate (poly-si + $SiO_2$) and $p^{-}$ silicon operate as capacitator.
But how are voltages and charges are applied? In order for inversion to occur, there should be charges formed in poly-Si, ...
4
votes
3answers
5k views
Why do we use Root Mean Square (RMS) values when talking about AC voltage
What makes it a good idea to use RMS rather than peak values of current and voltage when we talk about or compute with AC signals.
1
vote
2answers
170 views
Nodal Analysis of an electrical circuit
I have several doubts about solving circuits.
Can any circuit be solved using Nodal Analysis?
If some circuit can be solved using Nodal Analysis, can it be solved using Mesh Analysis too?
Why do we ...
-1
votes
2answers
2k views
How do I calculate output voltage from a given supply voltage and resistance?
I have searched everywhere but I can't seem to find out how I can calculate the output voltage (or voltage over a component) from the resistance of a resistor (or other component) and the supply ...
4
votes
2answers
933 views
Strategies against 50 Hz mains hum on detector signals?
I'm having problems with a strong 50 Hz mains hum on signals created by photodetectors. I assume that they are due to ground loops and I realize that the best option would be to remove those. What are ...
5
votes
4answers
2k views
Resistor circuit that isn't parallel or series
What's the equivalent resistance in this circuit (between points A and B)?
-2
votes
1answer
200 views
what is the proper way to connect two light bulbs in a circuit? in series or parallel?
What is the proper way to connect two light bulbs in a circuit? in series or in parallel and why?
My thought is that it's better to hook them in parallel, since if we take into account Ohm's Law, the ...
3
votes
0answers
234 views
Turn-on delay time for Laser diode
Do you know any simple explanation on the reason why the turn-on delay time on a laser diode is reducing while we increase the bias current?
Turn on delay,is the time that the laser needs from the ...
1
vote
1answer
977 views
How to calculate the charge and the potential across a charged capacitor charging an uncharged capacitor?
Initially, there is a single capacitor $A$ attached to a power source that charges it to a certain voltage $V$. Once it is charged, it is instantaneously removed and placed in a circuit with an ...
1
vote
0answers
76 views
Simplifying a biquadratic filter equation [closed]
I am trying to calculate input impedance of a multiple feedback low pass filter. What I need is the symbolic expression as simple as possible so that later I fill in the values and get the impedance ...
2
votes
1answer
363 views
Electrical flow in a simple parallel circuit
I'm having trouble understanding something in one of my text books:
Let’s have a look at the implications of each circuit configuration.
Figure 3.13 shows the Conventional representation of a ...
3
votes
2answers
304 views
The role of resistor in e.g. an AND gate
What is the role of the resistor in e.g. an AND gate like this one? :
One often sees lots of resistors in electric circuits, but I haven't really understood their role.
0
votes
3answers
2k views
Calculating time for a fully charged UPS
I have a UPS of 1000 Volts connected with 2 batteries each of 150 Amp. How much time it will take to consume the whole UPS (after fully charged) when a device of 1Amp is getting electricity form that ...
4
votes
5answers
3k views
What would be the effective resistance of the ladder of resistors having n steps
I'm a tutor. This is a high school level problem. In high school, every one have might have solved a problem of effective resistance of a ladder of resistors having infinite steps. Now the problem is ...
0
votes
1answer
155 views
Waveforms for a given ideal inverters circuit
I have the following circuit. All the inverters are ideal CMOS.
I need to draw the waveforms for each point (A, B, D, E, Vo), given that waveform at input.
What I want to ask is if what I did so ...
6
votes
2answers
686 views
Lots of little questions about radiation of LC circuits
I'm trying to get a more intuitive understanding of resonant inductive coupling. It's supposed be a more efficient way to transfer electrical energy wirelessly, because the coils are only coupled by ...
