0
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
Specify the crystal frequency required for an 8085 system to operate at 1.1mhz?
The crystal frquency in an 8085 system is twice the desired clock frequency, so a crystal of 2.2 MHz is required to operate at 1.1 MHz.
Note: Clock frequency is not the same as instructions per second, because the instructions in an 8085 take a variable number of clock cycles, between 4 and 18, to execute.
10.2 kilo ohms is the resistance necessary for 1 volt to induce a current of 98.04 micro amperes. Ohm's law: voltage equals current times resistance.
How do you construct an n type semiconductor?
An n-type semiconductor is formed by doping a pure semiconductor (silicon or germanium, for example) with atoms of a Group V element, typically phosphorus or arsenic. The dopant may be introduced when the crystal is formed or later, by diffusion or ion implantation.
Why does a ac voltage applied across a load resistance produce alternating current in the circuit?
Because V = I x R or Voltage = Current x Resistance. Since resistance is linear there is a linear relationship between Current and voltage. If you have DC voltage you have DC current and if you have AC Voltage you have AC current. Note that there is a linguistic recognition of this relationship in that the voltage is described in terms of the current.
What terminal does electrons flow from in a dry cell?
That is a good way to run the cell down quickly.
Electrons are negatively charged so they always move from the positive terminal towards the negative.
Each electron carries a charge of 1.602 x 10-19 coulombs so 1 coulomb (1 amp for 1 second) carries 6.24 x 1018 electrons.
Dc and ac analysis of Differential amplifier?
DC Analysis: For this analysis, frequency is made zero and the voltage of the source is increased in small steps from 0V.And the output voltage is plotted. So, finally we get a Vout vs Vin curve. AC Analysis: In this analysis, we choose an AC source. We keep the Offset voltage = 0V, AC voltage or small signal voltage = 2V (You can take any voltage you wish and it doesnt matter). So, to plot the ac response or frequency response of the circuit, increase the frequency in steps and note the output voltage. from this analysis , we can find the gain of the circuit over frequency.
biasing is nothing but addition of sufficient DC voltage source in the transistor circuit so that the transistor always remains in ON state. The AC signal has both positive and negative cycles , there is no problem with positive cycle , only negative cycle bothers us because the negative cycle makes the emitter-base junction reverse biased this brings the transistor to a cut-off state. To avoid this we bias the transistor with a DC voltage so that the emitter-base junction is always forward biased.
For an AC signal let the peaks be(+A,-A)
suppose that a DC voltage of V volts is applied then the peaks would change to (V+A,V-A) here we must always ensure that V>A
Current equals Voltage divided by Resistance. 9/2=4.5 amps.
A multimeter is used to measure three electrical characteristics in circuits: Voltage Current and Resistance. AC and DC voltage and current can be measured. These three are related by Ohms law: Voltage ( in volts) = Current (in amps) times Resistance (in ohms) see http://en.wikipedia.org/wiki/Ohm%27s_law
The main component in a multimeter is a micro amp meter. A hair thin wire is wound around an iron core on a pivot and with in a permanent magnetic field. When current flows through the coil it produces a magnetic force proportional to the current that causes the coil to move on the pivot against the permanent magnetic field. A pointer is attached to the coil and it move past the meter scale.
The coil has some resistance 50 Ohms. If one volt of direct current is applied the 200 Milli amps of that current would turn the coil with so much force that it would pin the needle or break the mechanism. Typical micro ammeters are limited to 50 micro amps maximum.
In a parallel circuit current divides inversely proportionally to the resistance. If a wire of 0.5 ohms is placed in parallel with the meter coil then 99% of the current will go through the wire (shunt) and 1% will go through the coil. The meter range would become 5000 micro amps or 5 Milli amps. If the shunt was made to .05 ohms the range would be 50 milli amps.
Instead of a shunt a resistor of 4,950 ohms is wired in series with the coil. Now the total resistance is 5,000 ohms if 100 volts is placed across the meter and shunt the meter will only show 50 micro amps.
Why fixed bias is called fixed bias?
I know nothing about fixed bias,So I try this web to know but this web address fail to answer my question.
What_is_fixed_bias_circuit
this is a fake web it can't help anyone
Sudip
What is the formula to calculate AC resistance if the DC resistance is known?
AC resistance is the term used to describe the elevated value of resistance due to the reduction in a conductor's effective cross-sectional area due to the the skin effect caused by an alternating current. The skin effect describes how AC current tends to flow towards the surface of a conductor, rather than being distributed across the entire cross-sectional area as is the case for a DC current.
For 50/60 Hz supplies the skin effect is not great and, so, there will not be a great difference between the DC resistance and AC resistance of a winding. Accordingly, it will be very difficult to calculate the winding's AC resistance, as its value is likely to be masked by experimental error and the accuracy of the instruments.
In theory, by using a wattmeter and an ammeter, the resistance of a load -in this case a winding- the readings can be inserted into the equation: R = P/I2. Using a DC supply will reveal the (DC) resistance value, and using an AC supply will reveal the AC resistance value. As explained, a combination of experimental error and instrument accuracy is very likely to mask any actual difference between the two resulting values.
So, at mains' frequencies, the difference between AC resistance and actual (DC) resistance would be very difficult to determine with any degree of accuracy.
What are at least five examples of materials that are good conductors?
copper wire, metals, water, poles, airplanes
Silver
Copper
Gold
Iron
Ionized air
lead
water with dissolved minerals
graphite
But it also depends on which you wish to conduct.
For thermal conductivity, the top group, in order of merit, are graphene, diamond, silver, copper.
For acoustic (sound) conductivity, you need a rigid non - lossy material, and Beryllium is probably at the top, but with similar metals such as tungsten and steel not far behind.
And Brahms and Bach have their followers in the music field.
Ohm's Law states Voltage = Current x Resistance. You rewrite the equation as Current = Volts / Resistance to solve for current.
How do you calculate internal resistance?
You need to use the formula E = IR + Ir
where: E is the e.m.f. of the power supply (the theoretical maximum voltage across the terminals when no current is flowing)
I is current
R is resistance of the circuit (load resistance)
and r is the internal resistance of the power supply.
Therefore, you can rearrange this formula to give r:
E = IR + Ir (Subtract IR)
E-IR=Ir (divide by I)
(E-IR)/I=r or r=(E-IR)/I
How much current at 240 volts passes through a wire with a resistance of 100 ohms?
current = voltage/resistance
Assuming the 240 volts is across the 100 ohm wire, 2.4 amperes
power = current * voltage
Resulting in the wire dissipating 576 watts... One hot wire!
What is the difference between npn and pnp transistor?
In NPN transistor, Base is connected to positive terminal of battery.
Now, when current is switched on, Base-Emitter junction (indicated in image) is forward biased, whereas Base-Collector junction is reverse biased.
Remember that forward bias narrows depletion region, whereas reverse bias widens depletion region.
n-type region(lower one) on emitter side has majority electrons (reason 'n' stands for negative).
These electrons move from emitter side to base.
Base is thin region, which has holes. When electrons move from emitter to base only a few electrons combine with holes. Whereas others pass from base to collector.
In collector the electrons are pulled by positive terminal of battery(right hand side battery). And thus the cycle of current continues to flow.
That is whole working of NPN transistor.
What are the components of a resistor?
Resistance is the property of a component which restricts the flow of electric current.
How does a transistor work as a switch explain with diagram?
In brief and in the most general terms, a transistor is a 3-terminal semiconductor device capable of changing its resistance in a "controlled" way. It is like the valve (the hose bib) that you open to turn on the water to your hose. The valve allows you to apply a little energy (from your hand) to control lots of energy (the water pressure). That's amplification. Let's peek in on this and make some simple comparisons. A transistor has an emitter, a collector and a base. The emitter and collector could be considered "input and output" terminals in the most basic sense. As for the base, it is the "control terminal" just like the handle on the faucet. By applying a small voltage to the base to "turn on" the device, we can get current to begin flowing. First a little, and then, by turning it on more, a lot. Eventually the device will be "all the way on" and will be allowing maximum current to flow through it. The opposite will be true when we turn the device off. That's it. Oh, but let's take a moment to look at the implications, shall we? Imagine turning on the water really, really fast. Like almost instantly on. Then off the same way. By turning the transistor on and off "instantly" and looking at the result, we'd get "ons" and "offs" from it. That's 1's and 0's there, and it's binary. That's how we can make a digital signal. And this process is exactly at the heart of how the microprocessor in all digital computers works. You probably saw that coming. Let's look at one other thing. You're familiar with sound, which is mechanical energy. It's like a vibrating string on a guitar or the membrane ("skin") on a drum, just to cite a pair of examples. That movement creates harmonic or oscillating motion and the sound. If we want to create the electrical equivalent, we have to open and close that water valve as quickly as the frequency of the vibrations. That's not really possible with the valve, but with the transistor, we can apply a changing voltage to the base as fast as any "regular" mechanical vibration. If a string vibrates at 1000 cycles per second (1000 Hertz), we can change the voltage to the base at that rate. Let's slow the action down. Note that we start turning on the transistor, then we turn it on a bit more, then a bit more. At some point we've reached a "peak" and then we start turning it off, and off a bit more and off a bit more until it's off. The rateat which we do this corresponds to the frequency of the signal being amplified by the transistor. And how far we actually turn the transistor on before turning it back off corresponds to the amplitude of the signal we are working with. The transistor has largely replaced the vacuum tube, which was originally called an electronic valve. Having wandered around in this discussion, you may be able to see why the terminology (which is a bit "old school" now) can still be fairly applied - even to the transistor.
What limits the current that flows through a circuit for a particular appllied DC voltage?
The voltage applied and the resistance across it.
What is the procedure for measuring current?
A: The procedure is very simple must have a voltmeter and must have a very low value of shunt in series with the circuit whereby the IR drop will be converted into amps. That works for DC only. For AC the signal is rectified and then measured or a flux clamp can measure the current
What process will double the power dissipated by a resistor?
Increase the voltage across the resistor by 41.4% .
Is industrial current is ac or DC?
The current that is transferred through cables over long distances is AC. The main reason for this is because it is easier to handle. For example, it is easy to convert an AC current to a higher or a lower voltage with transformers. Transformers don't work for DC.
