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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
Circuit diagram of 4bit synchronous counter using IC 7476?
Sadly, this website doesn't support graphics.
What are three characteristics of series circuit?
There is one and only one current path through it.
The current at every point in the circuit is equal.
The sum of the voltage drops across each element in the circuit is equal to the supply voltage.
The effective resistance of the circuit is equal to the sum of all the individual resistances.
RMS stands for root mean square. RMS is a method for measuring complex AC waveforms. It produces a voltage reading where the constantly varying AC voltage would do the same work as the equivalent DC voltage.
For instance, the standard US outlet voltage is listed as 120V. If you look at the AC waveform on an oscilloscope, you would see the voltage vary from +170 volts to -170 volts for a total of 340 volts peak-to-peak.
Now, if you apply the voltage to, say, a heating element, the voltage would do the same work whether it was positive or negative, so the 170 volts is the value that we would use, not 340.
BUT, being a sinusoidal AC wave, the voltage is not always 170. It varies all the way from near zero to the peak value of 170, so the voltage would not heat the element as hot as a constant (DC) 170 volts would.
If you measure the voltage at many points along the waveform, square each reading, average or calculate the mean of all the squared readings, then take the square root of the average (mean), you end up with a number that represents an equivalent DC voltage that would do the same work. In our example, it would heat the heater as hot. Voila! RMS!
This average is well known for simple sine wave voltages, such as what you would find at your receptacle. The RMS value is 0.707 X the peak voltage. So our 170V example: 170 X 0.707 = 120.19. The opposite is RMS X 1.414 = Peak, or RMS X 2.828 = peak-to-peak. So, 120 X 1.414 = 169.68.
But what if the AC waveform is non-sinusoidal, such as music coming out of an amplifier or impuse noise, or whatever? This is where RMS measurements are really useful, enabling us to find the equivalent power, or noise figure, etc.
For example, the voltage that comes out of a lamp dimmer is all chopped up, definitely non-sinusoidal. If you try to measure this voltage with various standard meters, you will get readings all over the map, because each meter will interpret the screwy waveform differently. If you use a "True RMS" meter, the results will be repeatable and stable, allowing valid comparisons to be made.
By the same token, amplifiers that are rated in "RMS Watts" are fairly well representative as to the actual power you can expect them to produce. Some manufacturers rate their amps in what they call "Peak Power". Remember above how an RMS voltage of 120 is also a peak voltage of 170? This lets the unscrupulous manufacturers put bigger numbers to their amps, making them appear more powerful. Now you know better!
Piezoelectric crystal is used in which device?
The piezoelectric crystal is used in transducers in ultrasound medical imaging. The crystal vibrates when an electric field is applied to it, the oscillations of the crystal vibrating occurs at very high frequencies beyond the threshold of human hearing.
Calculate the power out put of an amplifier that has an input of 15 μw and a gain of 25dB?
If you want to work in watts, convert 25dB to a scalling factor:
3dB = 2 x input
10dB = 10 x input
20dB = 100 x input
...25dB = 10 ^ (25/10) = 316.2 x input
So the output is 15 micro Watts x 316.2 = (4700)/(10^6) = 4.7 milli watts
If you want to work in dB, then convert 15 micro watts to dB:
10 * log |P| = dB = 10*log |15 x 10^6| = -48.2dB
***When you have very small (ie negative) dB, it is often referred to in dBm, or 1/1000 of dB ( 30 dBm = 0 dB)
so the output is -18.2dBm + 25 = 6.8dBm, or -23.2dB
Can a 4 ohm receiver drive 3 ohm speakers?
If you connect four four-ohm speakers in parallel, the impedance will be equal to 1 ohm, and will allow the speakers to run at the advertised watt RMS. The equation is 1/(total impedance) = 1/(impedance 1) + 1/(impedance 2) and so on.
Parallel is like this:
Power source: +
Speaker+: + + + +
Speaker-: - - - -
Power source: -
However, usually if you hook up a 4 ohm speaker to a 1 ohm amplifier, it would still function it would simply not provide nearly as much wattage as it would have otherwise.
Also, if your speakers are dual voice coil (like many subwoofers) you could use 2 4 ohm speakers, connecting the two voice coils on each speaker in parallel and then connecting the speakers themselves in parallel.
What is meant by the resistance of an electrical component?
Think of it like this:
Friction causes you difficulty in pulling heavy objects on a carpet. This frictional force is similar to electrical resistance. It is one of two ways to define how easily electricity will travel through an electrical element.
A 555 timer basically consists of:
# A voltage divider circuit, # Two comparators, # An SR flip-flop, and # Two (bipolar) transistors: one NPN (discharge) and one PNP (reset),
as can be seen in its block diagram.
The voltage divider consists of three 5Kohm resistors, so that we get (1/3)Vcc and (2/3)Vcc; we use these voltages as references for the comparators.
The three 5K resistors, along with IC's main applications being in timer and multi-vibrator circuits, give it the name 555 timer.
Why silicon is preferred over germanium as a semiconductor?
The oxide of silicon is a stable insulating insoluble solid, making it possible to integrate the metal interconnects in planar layers over the semiconductor.
The oxide of germanium is unstable and soluble in water, making it necessary to connect the integrated components with individual wires which is far too labor intensive and is also impractical for integration levels beyond MSI. Texas Instruments made some prototype SSI germanium ICs this way in 1958 and 1959 but abandoned the process when they licensed Fairchild's planar silicon IC process.
No ICs are made of germanium now, only discrete transistors and diodes.
Some work has been done on ICs made of silicon-germanium alloy, but I am not sure of the current status.
What is difference between mechanical and electromechanical device?
Mechatronics is typically defined as the intersection of the following fields:
* Mechanical Design * Electrical Design (e.g. electronics) * Software * Control Electromechanical engineering does not typically involve software or control topics directly. Rather, it is the study of systems where energy is converted between the electrical and mechanical realms.
It is 100+j(500-300) ohm = (100+j200) ohm = 223.6<630 ohm
Why does the resistance of a thermistor decrease as the temperature rises?
Some materials have negative temperature coefficients of resistance, and some have positive temperature coefficients. Carbon is an example of a substance with a negative thermal coefficient of resistance, so it's resistance will decrease as it gets hotter.
What is the substrate of isomerase?
the substrate in isomerase is protein, the myth that is fructose is absolutely a lie.
BUT WAIT?
have you noticed that 'iso' is a type of triangle
TRIANGLE??
ILLUMINATI
the substrate is illuminati
What is thermal runaway in a BJT?
Thermal runaway is where the biasing and operating point is such that the temperature causes the gain to increase, which causes the temperature to increase, which causes the gain to increase, in a vicious circle, leading to destruction of the BJT. Proper biasing and gain management can prevent this from occurring.
What is the term valance band?
It refers to the energy levels in an atom where the electrons that participate in bonding occupy. These energy levels correspond to those of the s and p orbitals of the outermost shell of the atom being considered.
In a DC suppy the frequency is zero. Why?
Frequency, as regards voltage, is a term applied to changes in the voltage per unit of time. As the voltage of the DC (direct current) supply does not change, it does not "cycle" like an alternating current (AC) supply. The frequency of oscillation of the voltage is zero cycles per second, or zero Hertz.
Does every different conducting substance have a unique resistivity?
Please note that resistivity also depends on temperature.In the most general case, the answer is definitely NO; all superconductors have the same resistivity, namely zero.
Other than superconductors, take a look at a table with some typical resistivity values. It would seem quite obvious that for a given temperature:
* Two different substances will, in general, have different resistivities.
* In practice, in some cases the difference in resistivity might be too small to reliably measure.
* It should be possible to find two substances that have the same resistivity at a very specific temperature - since the temperature-dependence will vary from one material to another.
* Likewise, it should be possible to design a mix of two substances, which exactly matches that of another, given, substance.
What tends to decrease reactive power in a circuit?
By adding capacitors or inductors in series (typically lower power) or parallel (higher power power factor correction); the choice of capacitor or inductor depends on whether the reactive resistance is "leading" or "lagging". A capacitor is modelled 1/jCw, where w = frequency in rads; an inductor is modeled jLw. If you know the reactive resistance, and the system frequency, you can calculate how much capacitance/inductance is needed.
How can you express ohms law in mathematical?
Voltage = Current * Resistance
ANSWER: 1000V = 1000 I = 1000 Ohms does not compute
It is a relationship that states if there is 1 ohm and 1 volt there will be =1 amperes flowing. The number can change but the relation ship will not
Diffrence between analog and digital computer?
An analog computer is any computer that represents its data in the form of continuously variable signals instead of the discontinuous encoded symbols used by digital computers.
The electric force that makes current flow in a circuit is related to the what?
The electric force that makes current flow in a circuit is related to the resistance.
What are the parts of a transformer?
A transformer has input and output connections, a primary winding (with or without taps) and a secondary winding or windings (with or without taps). It also includes a core and appropriate wrappings, and (perhaps) a housing. Some kind of accommodation will have to be made for mounting it mechanically.
