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Electronics Engineering

Electronics Engineering is a branch of engineering that deals with practical applications of electronic components, devices, systems, or equipment. Electronics are devices that operate on low voltage sources, as in electron tubes, transistors, integrated circuits, and printed circuit boards and use electricity as part of its driving force.

24,372 Questions

What are the four features required to construct a working simple circuit?

To construct a working simple circuit, you will need a power source (such as a battery), a load (such as a light bulb or a motor), conductive pathways (wires) for the electricity to flow, and a switch to control the flow of electricity.

What is the difference between volts and current?

Electrical current is the number of elementary charge units (coulombs) that pass by a given point in one second. Current, measured in amperes, is coulombs per second.

Electrical voltage is the "pressure" behind that current. Voltage, measured in volts, is joules per coulomb.

23V 470 ohms what is P?

23 volts across 470 ohms will dissipate about 1.1 watts.

Power equals voltage squared divided by resistance.

How do i fine an expression for power that involves only current and voltage?

You do not need ohm's law to relate power to current and voltage. Power is current times voltage. If you know current and voltage, you do not need to know resistance.

What is avalanche break down in scr?

Avalanche breakdown in Silicon-Controlled Rectifiers (SCRs) refers to the rapid increase in current flow through the device due to high reverse voltage. This phenomenon occurs when the reverse voltage exceeds the breakdown voltage of the SCR, causing a sudden breakdown of the junction and a rapid increase in current flow. Avalanche breakdown can damage the SCR if not properly controlled.

Formula for rotor speed on a cage rotor induction motor?

The formula to calculate the rotor speed (N_r) of a cage rotor induction motor is given by: N_r = (120 * f) / P, where f is the supply frequency in Hz and P is the number of poles in the motor. This formula assumes the motor is running at near synchronous speed and neglects slip.

Name type of circuit load which the apparent power is greater than the active power?

these two types of circuit loads are the purely capacitive loads and purely inductive loads

Another Answer

Apparent power will be larger than true, or active, power in ANY circuit, other than a purely-resistive circuit or an R-L-C circuit at resonance.

How Radar range related to Antenna gain?

Radar range is affected by various factors, including the transmitted power, beamwidth, frequency, propagation losses, and antenna gain. Antenna gain plays a crucial role in determining the effective range of a radar system, as it focuses the transmitted energy in a particular direction, increasing the signal strength in that direction and consequently extending the radar range. A higher antenna gain typically results in a longer radar range by improving the system's ability to detect and track targets at greater distances.

Is molten sulphur a conductor?

No, because molten sulfur is not ionic or metallic, so even if it did conduct, it would be a very, very poor conductor.

How many volts is 600 ohms?

To calculate the voltage across a 600-ohm resistor, you also need to know the current passing through it. Using Ohm's Law (V = I * R), where V is the voltage, I is the current, and R is the resistance, you can determine the voltage.

Why carbon has very low resistivity while coal or hydrocarbon have high resistivity?

High resistivity is the inverse of conductivity, and Carbon is not a good conductor (although it could be a better conductor than most hydrocarbons). Here are a few examples:

Carbon - 0.07 x 106 S cm-1 (not a good conductor)

Silicon - 1.2 x 10-5 S cm-1 (not a good conductor - used for this purpose in microchips)

Copper - 59.6 × 106 S cm-1 (good conductor)

Atoms in metals (good conductors) are held together by bonds between nuclei and their electrons. Atoms in nonmetals (bad conductors) are held together due to the atmos' sharing of valence electrons (ie covalent bonds).

Conductivity has to do with how easily electrons can move. In metals, electrons are more free to move than nonmetals, resulting in better conductivity. Silver is the best conductor, I believe. Sorry for the run around, but the basic answer to your question is this: I suspect in hydrocarbons, the valence electrons are more restricted due to the covalent bonding to the hydrogen atoms.

Do electrons move from negative to positive terminals?

Yes, electrons flow from the negative terminal to the positive terminal in a circuit. This is because electrons are negatively charged particles, and they are attracted to the positive terminal.

What is the function of engine?

Assuming you are refereeing to a physical engine not one of the software variety. Its to propel motor vehicles.

Next time Phrase your question better and then you will get a better anwser.

What is the difference between impressed voltage and induced voltage?

Impressed voltage is the external voltage applied to a circuit, whereas induced voltage is generated within a circuit due to a changing magnetic field, typically caused by electromagnetic induction. Impressed voltage is controlled by an external source, while induced voltage is a result of the circuit's own dynamics.

What is the total voltage a normal home uses?

Total voltage that you use in your home is constant. For Europe ~230V, for US ~120V. But the total power that you use differs and depends on total power consumption of the devices you use [Watt/h].

Does the short or long wire get hottest in a circuit?

This will depend on the circuit configuration, and the wire.

For two equivalent types of wire (same covering, thickness, cross section, but different lengths) in a series circuit, where the surrounding on both wires is kept equivalent, heating will be equal per unit length (meaning the wires will reach the same temperature); The longer wire will use more power, which will cause more room heating (due to the longer length), but the wires themselves will reach the same temperature.

For the same two wires in a parallel circuit, the smaller wire will heat up more due to a larger current flow through it, thus a higher I^2 * R loss (heat loss) per unit length.

If two wires are put in parallel, and have different lengths, but are made to have the same resistance, the exact same amount of current will flow in each, but the shorter one will inherently have a higher resistance per unit length, causing it to become hotter than the longer wire.

When there is no current passing through a conductor you say magnetic field is zero but in a conductor charges are in motion then why is there no magnetic field?

When there is no current passing through a conductor, charges are stilll in motion, but they are disorganized and not flowing. The magnetic fields by all of those random movements cancel each other out. That is why there is no magnetic field in a conductor with no current, even though there is movement in the charges.

When are voltage and current out of phase?

Because the impedance of the inductor and capacitor is not a real resistance / has an imaginary value that causes voltage and current to be out of phase.

An inductor's impedance is equivalent to j*w*L (j = i = imaginary number, w = frequency in radians, L = inductance), while a capacitor's impedance is 1/ (j*w*C).

The 'j' causes the phase shift.

What causes the current to decrease as an induction motor accelerates?

The current in an induction motor decreases as it accelerates due to reduced rotor impedance and increased back EMF. As the motor speeds up, the rotor reacts with the rotating magnetic field produced by the stator, causing a decrease in the current needed to maintain acceleration. This decrease in current helps to improve the motor's efficiency and reduce energy consumption.

Why are a range of voltages used?

Several reasons for different voltages. At the heart of it is that to deliver the same power, voltage and current are inversely related. The other aspect is safety.

So for the grid, high voltages are used to maximize power transmission within the current limits of the cables.

In industrial environments, equipment may require a lot of power - that requires high voltages as well

Domestic requirements are not so power-hungry so 120 or 240 volts are adequate, and are also safer (well... less dangerous) than higher voltages.

How do you make Light-dependent- resistance circuit?

A Light Dependent Resistor (aka LDR, photoconductor, or photocell) is a device which has a resistance which varies according to the amount of light falling on its surface.

A typical light dependent resistor is pictured above together with (on the right hand side) its circuit diagram symbol. Different LDR's have different specifications, however the LDR's we sell in the REUK Shop are fairly standard and have a resistance in total darkness of 1 MOhm, and a resistance of a couple of kOhm in bright light (10-20kOhm @ 10 lux, 2-4kOhm @ 100 lux).

Uses for Light Dependent ResistorsLight dependent resistors are a vital component in any electric circuit which is to be turned on and off automatically according to the level of ambient light - for example, solar powered garden lights, and night security lighting.

An LDR can even be used in a simple remote control circuit using the backlight of a mobile phone to turn on a device - call the mobile from anywhere in the world, it lights up the LDR, and lighting (or a garden sprinkler) can be turned on remotely!

Light Dependent Resistor CircuitsThere are two basic circuits using light dependent resistors- the first is activated by darkness, the second is activated by light. The two circuits are very similar and just require an LDR, some standard resistors, a variable resistor (aka potentiometer), and any small signal transistor

In the circuit diagram above, the LED lights up whenever the LDR is in darkness. The 10K variable resistor is used to fine-tune the level of darkness required before the LED lights up. The 10K standard resistor can be changed as required to achieve the desired effect, although any replacement must be at least 1Kto protect the transistor from being damaged by excessive current.

By swapping the LDR over with the 10K and 10K variable resistors (as shown above), the circuit will be activated instead by light. Whenever sufficient light falls on the LDR (manually fine-tuned using the 10K variable resistor), the LED will light up.

Using an LDR in the Real WorldThe circuits shown above are not practically useful. In a real world circuit, the LED (and resistor) between the positive voltage input (Vin) and the collector (C) of the transistor would be replaced with the device to be powered.

Typically a relay is used - particularly when the low voltage light detecting circuit is used to switch on (or off) a 240V mains powered device. A diagram of that part of the circuit is shown above. When darkness falls (if the LDR circuit is configured that way around), the relay is triggered and the 240V device - for example a security light - switches on.

NEW For details of a more advanced light/dark sensor circuit click here to read our new article LM741 Light/Dark Sensor Circuit. We have these circuits available for sale.

How do you convert 24 vac to 5 vac?

You can use a transformer with a turns ratio of 24:5 to convert 24 VAC to 5 VAC. This means the primary winding has 24 turns for every 5 turns on the secondary winding, which will step down the voltage proportionally. Make sure the transformer is rated for the appropriate power and frequency.