# Questions tagged [theory]

Theory is a contemplative and rational type of abstract or generalizing thinking, or the results of such thinking. Depending on the context

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### Flow of current, isn't make potential difference?

I've learn some electronic knowledge at school and so confused by some questions. Q1. IS it possible a flow of electricity without an electric field? Q2. I've learn that moving of particle with ...
2answers
702 views

### BJT Voltage Divider Bias Circuit Theoretical/Ideal Model Help ..LTSPICE?

simulate this circuit – Schematic created using CircuitLab I've been trying to study BJT Voltage Divider Bias Circuits. In particular, as they relate to their active region, amplification, and ...
2answers
102 views

### How can I calbrate my power meter?

I used to work for a company that made power meters but only worked on the desktop application (user interface) side of things and never really learned completely how some processes occur, like the ...
2answers
173 views

### “Current is pulled not pushed” they say. Doesn't the transistor working the other way around? [closed]

The emitter current is defined by hfe and the base current not the load. The load does not "define" Iemitter.
1answer
99 views

### Flow of electricity. Need explanation [closed]

simulate this circuit – Schematic created using CircuitLab People are taught how to calculate this very simple thing, and the calculation goes from source plus to minus, and the diode is there ...
5answers
8k views

### Is there a formula to determine the size of decoupling capacitors? [duplicate]

I have used many decoupling capacitors in circuits and have seen them in many textbooks, but they never give an explanation about why they picked a certain size of capacitor. Everyone seems to have a ...
1answer
315 views

### Theoretical: Would it be possible to have a worldwide AC standard at 55hz

The question comes from a discussion I had years ago with a keyboard player who had perfect pitch. His problem came from the fact that he lived in a very small appartment in an old building and he ...
3answers
2k views

### Subthreshold regime advantages/disadvantages

Could someone explain the most important reasons for an analog designer to use MOSFET transistors in the subthreshold regime? What are the advantages and disadvantages? Generally, the circuits in mind ...
0answers
297 views

### Cgs,Cgd capacitor in Mosfet/ problem with measurement unit

I am a little confused with this problem. I would like to ask if I have a Mosfet(in saturation)and I have find that Cgs=16fF and Coverlap = 0.5fF/um(this is given in the description of the exercise), ...
1answer
210 views

### How to Convert between dB Voltage and Power

We read that the formula for expressing microvolts in decibels is different from that for milliwatts by a factor of 2: $U = 20\log_{10}{\frac{u}{u_0}}$ $P = 10\log_{10}{\frac{p}{p_0}}$ (Note ...
0answers
1k views

### Overdrive voltage and Early effect in MOSFET

Can anyone explain to me if there is the Early effect in MOS transistor then the Early effect affects the expression for VOV which is $VOV=\sqrt{\frac{2ID}{kn'(W/L)}}$?
2answers
2k views

### Why are dependent sources not disabled with the superposition principle?

I've been wondering this recently. My intuition says that a voltage drop across a dependent source is no different than any other circuit element whose response depends on the inputs of one of the ...
1answer
112 views

### How much energy could we harvest from a 0.1V source (gedankenexperiment) [closed]

For the sake of a thought experiment, suppose two 10-metre balls appear magically somewhere on land. In the middle of the Sahara desert for example. The balls are the terminals of a perfect voltage ...
1answer
124 views

### What hypothesis are needed to support the following argument on a three phase system?

Given the following three-phase system: simulate this circuit – Schematic created using CircuitLab Suppose to set 2 wattmeters as follows: $P_{21}$ which measures current $I_2$ and ...
6answers
3k views

### Electricity through water can injure a person?

I have maybe a simple question.I would like to know if current can travel through water and can injure a person. For example as shown below(A little funny picture!!!) a man watering his grass and his ...
2answers
2k views

### The History of conventional current

I would like to ask why the first scientists choose the current flow from high voltage(High potential) to low voltage(Low potential) which we know that it's wrong.I had heard and read that they take a ...
2answers
400 views

### Explaining capacitance formula of electrolytic capacitor

As stated in this article at page 5, capacitance of a capacitor is generally expressed with the following formula: My question is about surface area S, where it is ...
0answers
502 views

### Conduction angle in three-phase rectifier

In a standard three-phase bridge rectifier, which consists of 6 diodes, each diode (or thyristor) conducts 120º of the full 360º period. I have built a synchronous rectifier (for research purposes), ...
1answer
391 views

### Must the characteristic impedance of a transmission line be non-real for it to be lossy?

In Does conductance in the transmission line model represent a physical quantity? it came up that a non-real characteristic impedance just means the line has some loss. With real transmission lines ...
1answer
36 views

### What determines current through a VS in parallel with a resistor?

This is more of a conceptual question with ideal voltage sources, I am fully aware of its impracticality, but bear with me for the sake of a theoretical discussion. Consider a simple circuit shown ...
2answers
208 views

### Electric networks with an open-loop

This is a generic concept question that I encountered during the first day of an EE course. Our lecturer told us that electric circuits are essentially electric networks with closed loops. I would ...
1answer
549 views

### What is “formal verification” of hardware?

I read that testing and verification are different but in what way? I read that somebody writes theory to prove that the hardware is "correct" but how is that done? I tried reading Wikipedia and ...
1answer
449 views

4answers
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### Why is there current flow in the sub-circuits?

I'm struggling with the theory of this(unusual) circuit: simulate this circuit – Schematic created using CircuitLab The load receives no power at all, due to the voltages cancelling out, yet ...
2answers
173 views

### How Would a CPU Improve if its Logic Circuits were Reduced? [closed]

Is there an estimate as to how a common CPU (for example, Intel i7) would improve if all of its logic circuits were reduced to their theoretical minimum, in the sense explained here? By "improve" I ...
0answers
58 views

### BJTs drawing collector current from a limited current source

simulate this circuit – Schematic created using CircuitLab Let's make everything ideal by ignoring the voltage drops: Q1's allowed collector current is: 22.4 mA Q2's allowed collector current ...
6answers
62k views

### Ceramic caps vs electrolytic. What are the tangible differences in use?

A quick google around and all I seem to be able to find are people talking about the physics & the chemistry of the capacitors but not how this affects choosing which to use. Avoiding talking ...
2answers
1k views

### Two batteries connected to a resistor

In the circuit shown here the conventional current direction is from V2 to V1 and is equal to 3 Amp. I understand the theory. But, if I make this circuit with two batteries, according to the schematic ...
1answer
758 views

### How does a cascode or beta-enhanced voltage amplification stage work?

I'm studying electrical engineering and we just finished a project where we had to build a power amplifier. But I think I can do better than what we did. I read Distortion In Power Amplifiers where ...
1answer
883 views

### Understanding microphone sensitivity

My goal is to figure out a relation between output voltage and input SPL: $$dB(SPL) = f(V_{out})$$ First, I get the sensitivity in volts from this formula: Sensitivity_{dB(V)} = 20 * log_{10} (...
2answers
1k views

### Is this measurement of a cricuit's output impedance valid?

The following circuit is a simple voltage regulator. The Vout is maintained at -1V, however the opamp in the circuit has a non-zero output impedance. This is represented by the resistor R1. simulate ...
1answer
1k views

### What is the explanation with shorting vcc and gnd to power up the whole circuit in a breadboard? [closed]

I was building a logic circuitry that performs 8 bit multiplier 16 bit divider using decoders as finite state machine in breadboards. the circuit is a bit large and i wonder why grounds or low voltage ...
2answers
761 views

### How to analyitically optimize an RLC “circuit” to reduce overshoot?

I have a "circuit," that's not really an electrical circuit but rather a physical process that follows the same functional form as an RLC circuit with regards to how it responds to excitations--...
3answers
810 views

### Understanding optocoupler performance with collecor or emitter resistors

When using an optocoupler, is there a difference performance'wise whether using a collector or an emitter resistor? When using a normal transistor the base to emitter voltage gain is approximately 1, ...