Circuits

Then I'll try this. Just as V=IR is the fundamental equation relating voltage, current and resistance for a resistor circuit, the following equation relates voltace, current and capacitance for a capacitor:

Or, if you are not familiar with that calculus term with the derivative, you can think of it as:

I(t) = C * (change of voltage per time)

So when you have DC, there is no change of voltage with respect to time, so there is zero current. When you have an AC voltage signal that varies across the capacitor with time, that equation lets you calculate the current that results through the capacitor.

A capacitor is two surfaces near each other, but not touching. A direct current "sees" a capacitor as an open switch. It cannot pass through. An alternating current "induces" a charge in a capacitor and can pass through.

Conductance (G) is the reciprocal of resistance (R), expressed as G = 1/R. According to Ohm's Law, resistance is equal to voltage (V) divided by current (I), so R = V/I. Therefore, conductance can be expressed as G = I/V.

A circle circuit is a mathematical model that represents a closed path in a network topology where data can flow endlessly in a loop. It allows for continuous communication between devices in the network without a defined beginning or end point. It is commonly used in systems where data needs to circulate without interruption.

A simple circuit consists of a power source (such as a battery), a load (such as a light bulb), and wires connecting them in a complete loop. When the circuit is closed, the power source provides electricity to the load, causing it to operate.

The charging time of a capacitor is usually lower than the discharging time because during charging, the voltage across the capacitor is increasing from zero to its maximum value, which initially allows a higher current to flow. During discharging, the voltage across the capacitor is decreasing from its maximum value to zero, resulting in a lower current flow. This difference in current flow affects the time it takes for the capacitor to charge and discharge.

Alcohol is used to measure at low temperatures because it has a lower freezing point than Mercury. Mercury has a higher boiling point than alcohol, mercury boils at around 400 Co and alcohol boils around 80 C0.

A high voltage, typically around 600 to 1000 volts, is applied to the paper in an electrophotographic (EP) process laser printer to transfer the toner from the drum to the paper. This electrostatic charge helps the toner particles adhere to the paper before being fused in place by heat.

Yes. Copper is a very good conductor. But a penny is not

a safe device to include in an electrical circuit.

An electric current is the flow of electric charge, carried by electrons in the conductor.

Unless, it is a conducting solution, in which case the currents may be moving ions carried by water.

Unless, it is the solar wind, in which case it is the stream of electrons and protons from the Sun carried by the vacuum of space and their own inertia.

So, just to be on the safe side, electric current is the flow of charge and it does not matter what the charge is and it does not matter whether it is in a condcutor or interstellar space as long as it is moving.

When a voltage is applied to a conductor, free electrons gain energy and move in response to the electric field created by the voltage. This movement of electrons constitutes an electric current flowing through the conductor.

A bar magnet is made from magnet materials and has a magnetic field at all times. An electromagnetic is not naturally magnet and only has a magnetic field when electricity is passed through it.

When a light bulb gives its last glimmer, it means that the filament inside the bulb has burned out. This results in the light bulb no longer being able to produce light. When this happens, the bulb needs to be replaced with a new one.

To understand what really happens, imagine a very thin wire, one atom thick. Further imagine that we can label these atoms individually, so that a particular very small section of wire looks like -A-B-C-D-.

An electron comes in from the left. That pushes one of atom A's electrons over to atom B, which in turn pushes one of atom B's electrons to atom C, and so on.

In a real wire, the electric impulse... the net flow of electrons... happens at, effectively, the speed of light (in whatever material the wire is made of). However, any individual electron moves at most very slowly through the wire. This slow movement is called the "drift velocity."

In a 3 ampere current flowing through an 18 gauge wire, electrons have a drift velocity of about a meter per hour.

The opposition to the flow of current in a circuit is called resistance. Resistance is measured in ohms and is represented by the symbol Ω.

A phase-shift oscillator using a PNP transistor consists of an RC network in the feedback path, a PNP transistor biased to operate in the active region, and a network of resistors and capacitors that provide the required phase shift for oscillation. The RC network introduces a 180-degree phase shift at the desired frequency, and the transistor provides the additional 180-degree phase shift needed for sustained oscillation. By properly selecting the values of resistors and capacitors, along with biasing the transistor correctly, a stable sinusoidal oscillation can be achieved.

If the voltage is doubled and the resistance is constant, Ohm's Law states that the current will also double. This is because the relationship between voltage, current, and resistance is linear, and increasing the voltage will directly increase the current flow.

Yes, the strength of an electromagnet can be changed by changing the voltage of the power source. Increasing the voltage increases the current flowing through the electromagnet, which in turn increases its magnetic field strength. Conversely, decreasing the voltage decreases the magnetic field strength.

Any two adjacent conductors can be considered a capacitor, although the capacitance will be small unless the conductors are close together for long. This (often unwanted) effect is termed "stray capacitance". Stray capacitance can allow signals to leak between otherwise isolated circuits (an effect called crosstalk), and it can be a limiting factor for proper functioning of circuits at high frequency.

Stray capacitance is often encountered in amplifier circuits in the form of "feedthrough" capacitance that interconnects the input and output nodes (both defined relative to a common ground). It is often convenient for analytical purposes to replace this capacitance with a combination of one input-to-ground capacitance and one output-to-ground capacitance. (The original configuration - including the input-to-output capacitance - is often referred to as a pi-configuration.) Miller's theorem can be used to effect this replacement. Miller's theorem states that, if the gain ratio of two nodes is 1/K, then an impedance of Z connecting the two nodes can be replaced with a Z/(1-k) impedance between the first node and ground and a KZ/(K-1) impedance between the second node and ground. (Since impedance varies inversely with capacitance, the internode capacitance, C, will be seen to have been replaced by a capacitance of KC from input to ground and a capacitance of (K-1)C/K from output to ground.) When the input-to-output gain is very large, the equivalent input-to-ground impedance is very small while the output-to-ground impedance is essentially equal to the original (input-to-output) impedance.

The particles that carry charge around a circuit are electrons. In some semiconductors, missing electrons in a crystalline structure (of silicon or germanium), caused by adding special impurities, form spaces called "holes" where there is a missing electron. These "holes" can also travel but, in the end, it is electrons that move in the opposite direction to fill those holes that carry the current.

In a parallel circuit, each bulb receives the full voltage of the power source, so all bulbs shine at their full brightness. In a series circuit, the brightness of each bulb decreases as more bulbs are added because the voltage is shared among all bulbs.

Yes, that's correct. Ohm's law is a fundamental principle in electrical circuits that states the relationship between current (I), voltage (V), and resistance (R) in a circuit. Mathematically, Ohm's law is represented by the formula: V = I * R, where V is voltage, I is current, and R is resistance.

V = (I) x (R) = 2 x 12 = 24 volts

When capacitors are connected in series, their total capacitance decreases. This is because the total capacitance is inversely proportional to the sum of the reciprocals of the individual capacitances. The voltage across each capacitor remains the same.