Electronics Engineering

Resistance: Electrical resistance describes how an electrical conductor (a wire) opposes the flow of an electrical current (flow of electrons). To overcome this opposition a voltage (a energy) must dropped (used) across the conductor (wire). Resistance can be described by ohms law: Ohms Law: R = V / I (Resistance = Voltage / Current) (resistance measured in ohms) where: Voltage [V]= the energy lost across an component (voltage measured in volts). Current [I] = the charge (electrons) flowing through an component (current measured in Amps). Electrical resistance can be thought of as sticking your hand out a car window. The faster [current] you drive the harder the wind presses [resistance] against you hand and therefore it takes more energy [voltage] to hold your steady. When trying to overcome electrical resistance, the electrical energy lost is turned into heat. This is how the elements of a household stove, toaster, and fan heater work. Because of the vacuum in a light bulb, the electrical energy lost is instead turned into light. It can be seen the electrical resistance plays a large role in modern life. Resistor: The resistor is the most common electronic component and is used to limit and/or control the voltage and current in an electronic circuit. Resistors are carefully manufactured to provide a predetermined value of electrical resistance which may range from 0.1 ohms to 100,000,000 ohms, depending on the application. The physical size of a resistor also varies dependant on the amount of power passing through the resistor, given by: P = V x I (Power = Voltage x Current) (power measured in watts) There are also many types of resistors including: · Variable Resistor - changes resistance when its shaft is rotated (volume knob on a stereo). · Thermistor - changes resistance when the temperature changes (used in a thermostat). · Light Dependant Resistor (LDR) - changes resistance when the lighting changes (used in children's night-lights). Resistor Example: An LED is a small red light (such as the one on the front of most TVs) and requires 2.0 volts and 0.02 amps to operate correctly. If we connected that LED up directly to a 12 volt battery, the voltage would be too high, and too much current would flow… the LED would blow up. We need to use a resistor to limit the voltage and current. But which value of resistance should the have resistor? Uses ohms law: R = V / I = (12.0 - 2.0) / 0.02 = 500 ohms (Note: the voltage across the resistor is the battery voltage minus the voltage we want across the LED) But which value of power should the resistor be capable of handling? P = V x I = (12.0 - 2.0) / 0.02 = 0.2 Watts hope this helps

The 74LS32 is a Quad Two Input OR gate with Low Power Schottky specifications.

In order to answer that, one would need to know what the circuit is designed to do (so

that he would know how to tell when the circuit is "working"), and would also need to

see the schematic diagram, in order to know exactly how the fixed resistor and the

thermistor are configured in the circuit, and what other components are involved.

Consider . . . If I came up to you on the street, or even for that matter in an Engineering lab,

and I said to you "I've got a circuit with a coil and a resistor in it. Will it work if the impedance

of the coil is greater than the resistance of the resistor ?", you would most certainly find

yourself at a loss, just as I do when I read your question.

zero

When checking continuity in a series circuit, you put your leads in series with the circuit or device being checked. You also make sure the circuit is deenergized and that it is open.

The component used to protect a LED from burning up is called a resistor.

it is an oscillator

sdrg

The db scale refers to the decible scale (measures noise intensity).

Simple addition, but it must be done with complex numbers.

A flip-flop can act as a memory storage device because a flip-flop has one of two states, and it does not change state, so long as power is retained, until told to do so. One flip-flop corresponds to one bit of memory.

more or less, yes

There is a school of thought residing with how much redundancy should be built in. obviously more redundancy should make it more reliable however those same additional parts could make the system fail as a consequence of additional redundancy.

The short answer is that with more individual coils in the rotor (and the increased number of commutator segments necessary to support them), the motor will run more smoothly. At each transition, the rotor will want to slow down a bit, but with a large commutator and lots of coils in the armature, the motor will transition more quickly to the next segment (for a given RPM) than a motor with fewer segments. The motor runs more smoothly. The drawback in making a motor like this is the increase in cost. A more economical motor is constructed using fewer windings in the rotor. The trade offs must be considered based on application and the economics of that application.

efreqw

Reginald aubrey fessenden

When a pn junction is reversed bias practically no current flows through it ,but a very small current flows through due to minority charge carriers ,which is known as reverse saturation current .In p type due to electrons and in n type due to holes .

while demodulating the modulated signal using coherent detection at the receiver end we need to generate the same carrier which is a very difficult ,it makes the receiver costlier and complex because the signal get distorted during the transmission process so generating the same carrier is quite impossible . if we are required to transmit the message to a large number of receivers than it will become very complex and costly.

secondly when we modulate and send a pilot carrier it become possible to detect the signal by envelope detection method which requires very less circuitry and is very cheap. provided the sum of maximum amplitude of carrier and the message signal must be greater than zero so that the envelope gets a lift up..

the disadvantage of this scheme is that the higher transmission power is required...

Gain in decibels is a logarithmic base 2 scale with a multiplier of 3, so 3 db is twice the power, 6 db is four times, etc. Gain of -3.5 db means a power loss of 21.17, or a ratio of about -2.25. Note, however, that this is power, not voltage. Since power is voltage times amperes, and since amperes is voltage divided by resistance, in order to achieve a power loss of 2.25, the voltage must change by the square root of that, so the voltage changed by -1.5.

seasning

NO. They do not oscillate.

huh