Electronics Engineering

VBS stands for Visual Basic Scripting. It is used for Win9x and later versions of windows. It can be used for registry maintenance, Command Prompt (CMD), and also for pranks (as I do so myself).

This is an example of a message box code:

x =msgbox("Hello",0, "This is a VBS message box")

Put this in notepad or wordpad and save as:

anything you want to name it.vbs

A closed circuit is a kind of electric circuit in which the path that the electrons follow forms a complete circuit.

It was developed by Dr. Sam Hurst. He invented the first touch sensor which was not transparent and hence not like the touchscreens like today in 1971 at Kentucky University.

In 1974, he developed transparent touchscreens we use these days and in 1977 the whole technology used today was developed and patented it.

The flow in a circuit is called the electric current and it is measured by voltages. The number of volts that are present in the charge will determine the strength of the electric current.

To understand how voltage standards for motors are set it is important to know the basics of the power systems they operate on. In general, utilities that supply power in the USA, and most other 60 cycle countries, are required to provide power to the incoming point of a facility in multiples of 120 volts. Thus incoming equipment, such as circuit breaker panels, are rated in multiples of 120 volts. The common voltages are 120, 240, 480, and 600.

In addition, utilities are obligated by the regional governing authorities, (usually called Public Utility Commissions) to regulate the voltage within a fairly narrow range such as plus or minus 5%.

For example, in most single phase residential systems the voltage is 120/240. It is brought to the building with 3 wires, one being a neutral and the other two having voltages 120 volts different from the neutral wire. The voltage difference between the two "hot" wires is 240 volts.

In 3 phase systems the situation is a bit different. There are 3 phase, 3 wire, ungrounded systems where the voltage between the three wires is 240 volts. The big brother of that system is the ungrounded 3 phase, 3 wire 480 volt system. Ungrounded systems are usually found in older facilities.

In newer installations, the two most popular systems are called 4 wire grounded wye systems. The low voltage version is represented by a 120/208 volt system. The higher voltage version it is a 277/480 volt system. On both of these "grounded wye" systems, the low voltage portion (120 or 277 volts) is only available as single phase. The high voltage (208 or 480 volts) is available as either single phase or 3 phase. It should be noted that in the 4 wire grounded wye systems the high voltage is 1.73 times (the square root of 3) higher than the low voltage. These grounded wye systems are generally felt to be safer and more flexible than the older ungrounded systems. The flexibility comes from the ability to handle single phase lighting circuits, that operate at 120 volts or 277 volts, from the same system that feeds the 3 phase circuits for motors, equipment for heating, air conditioning, elevators, and industrial machinery.

# voltmeters usually employ an electronic circuit that acts as an http://www.answers.com/topic/integrator,

# linearly ramping output voltage when input voltage is constant (this can be easily realized with an http://www.answers.com/topic/operational-amplifier).

# The dual-slope integrator method applies a known reference voltage to the integrator for a fixed time to ramp the integrator's output voltage up, then the unknown voltage is applied to ramp it back down, and the time to ramp output voltage down to zero is recorded (realized in an http://www.answers.com/topic/analog-to-digital-converter implementation).

# The unknown voltage being measured is the product of the voltage reference and the ramp-up time divided by the ramp-down time.

# The voltage reference must remain constant during the ramp-up time, which may be difficult due to supply voltage and temperature variations. .

Digital voltmeters necessarily have input amplifiers, and, like vacuum tube voltmeters, generally have a constant input resistance of 10 megohms regardless of set measurement range

There are 746 watts in 1 HP. Watts = amps x volts. It depends on the voltage rating of the motor. Amps = 746/volts = ? need voltage.

The brightness of three bulb would be mare than one

You can find the current by using an ammeter. The cheapest way (although more invasive) is to use a probe type ammeter or multimeter. To use, you need to insert the meter in the current path of the resistor (in series with the resistor). These meters are fairly cheap - as low as $8 if you shop around. If it is not feasible to break the circuit and insert the meter, and you have room around a wire going to the resistor, you could use a clamp on ammeter as well. These are typically more expensive.

If you understand resistor codes, you can also use a volt meter/multimeter to measure the voltage drop across the resistor (put the probe in parallel with the resistor). The current should be equivalent to I = V / R.

If you don't know resistor codes, do an online search to match colors with numbers. There should be three stripes. The first two are the resistance and the third is a magnitude. For example, if the first color matches the number 1, and the second matches 8, and the third matches 3, then this is a 18 x 1000 = 1.8k ohm resistor.

When a capacitor is powered off in an energized circuit, the capacitor still stores a certain amount of electricity. When there are other loads or components in the circuit, they will slowly discharge, or they can be quickly discharged by short-circuiting with small resistors or wires (at low voltage).

When the capacitor discharges, the two poles of the capacitor respectively carry a certain amount of charge, and the outside world and the capacitor form a closed loop (generally, the closed loop does not include a power supply). The excess electrons (negative charges) approach the positive electrode of the capacitor to form a current, so that the charges at both ends of the capacitor are neutralized. When the neutralization is completed, the electric field between the two electrodes of the capacitor disappears. However, this is in an ideal situation. The amount of terminal charge is exponentially neutralized towards zero, but not zero.

2. Discharge requirements of capacitors

3. After the capacitor is disconnected from the bus, it must be discharged through a discharge resistor or a special voltage transformer.

4. Discharge should be performed between the lead wires of the capacitor and between the lead wires and the casing.

5. The capacitor can be grounded after the capacitor is discharged.

6. Before working on the capacitor, be sure to conduct a test discharge. This discharge is to place the discharge rod on the terminal of the lead wire of the capacitor for a period of time.

7. Even if both sides of the capacitor device are grounded, in order to prevent residual charge on the capacitor, a test discharge must be performed, and each group of capacitors connected in parallel must be discharged.

8. Special care should be taken when conducting inspection discharge of capacitors removed due to faults. Due to the damaged capacitor, the general grounding device may not function as a ground discharge due to a partial disconnection.

9. If the capacitor device has an interlock device, it should be considered that only after the entire device is grounded, the small door of the capacitor bank protective fence can be opened.

We're JYH HSU(JEC) Electronics Ltd (or Dongguan Zhixu Electronic Co., Ltd.), an electronic components manufacturer. You may google "JYH HSU" to find our website.

The power consumed by an inductor is not zero since it's resistance is not zero either. The power consumed is just too minimal that it can be ignored. What the inductor does is, during one half of the Current's sinusoidal waveform, it stores energy in the form of magnetic flux. During the next half,it discharges the stored energy into the circuit by losing the magnetic field. Hence,they say it doesn't consume power. If the inductor's resistance was significant then you will see that it will consume power. Resistance and Reactive resistance are two different things.

It is considered a diode, a Light Emitting Diode (LED).

Current in a purely inductive circuit lags the voltage by 90 degrees. The apparent power in such a circuit will be zero, because the power factor is zero, however, energy will still be transferred, and VARs (Volt-Amps-Reactive) will be non-zero.

It is a semiconductor device with two terminals, typically allowing the flow of current in one direction only. It may also be termed as the electronic component with two electrodes known as the anode and the cathode. Most diodes are made with semiconductor materials such as silicon, germanium, or selenium. The diode acts as a valve in the electronic and electrical circuit.

There are two types of electrical generator.

One is a dynamo, which produces d.c.

The other is an alternator, which produces a.c.

the answer is Rectifier. it converts ac voltage into dc which can apply to the dc device

The differeces between frequency and amplitude modulation does not effect the range. Fundamentally the amplitude modulation system is less efficient in that a carrier is generated, which is modulated. The modulation power is half of the carrier power. The bandwidth required is twice the highest modulating fequency. Because of the small bandwidth required, the Amplitude Modulated band on radios is from 550 Khz to 1500 Khz. Channels are separated by 10 Khz, with actual users usually separated by 2 or three channels minimum. Frequency modulation varys the frequency of the carrier by the audio modulating component. While the frequency deviation can be as low as the audio frequency modulating the carrier, better noise performance is achieved by deviating the carrier by as much as possible. In commercial broadcast operations, the 15 Khz audio signal deviated the carrier by 75 Khz. This presents exceptionally good audio reproduction. It also causes the FM (Frequency Modulated) signal to occupy a band of about 240 Khz for a 15 Khz audio channel. This compares to 30 Khz for an equivalent AM (Amplitude modulated) signal. Because of the larger bandwidth required, the FM broadcast band is moved higher in frequency. This makes the other comments about range etc come into effect. AM signals can be received even when an interfering signal is present. Weak signals can be received in the presence of strong signals. Because of this property, Aviation signals, (Airplane to control tower and tower to plane) are in AM. FM signals have an effect called "capture effect" in which a stronger signal will capture the channel and eliminate interference from the weaker signal. Basically you are trading bandwidth for interference rejection. Because of this, signals from satellites, where the signal strength is extremenly small, used to be sent in FM. Present technology uses digital broadcast techniques.

Talking about digital, because of the ability of digital receivers to process signals of extremely small size, digital signals are being sent along with both AM and FM broadcast signals for either better quality, or supplementary services. Cell phones are all being switched over to digital technology for better reliability and better channel usage.

No, they cant take multiple paths because for one component of the circuit to operate it can bypass the other components to power that one. It does not require all components to be on(like a series circuit) for just one component to operate.

Power used in what?

Changing the potential difference in a circuit does not change the resistance. Rather, it changes the current.

A: Any feedback that contributes to the input is positive feedback

any feedback that subtract from the input is negative feedback

This is because of two reasons:

1. Primarily because SC test is performed at rated Current(as we calculate series parameters-leakage impedance-in SC test). As the rated current on hv side is much less than lv side(VI = constant), so the rated hv side current is easily achieved(compared to lv side). Vice-versa is true for Open circuit test.

2. Also because we cannot short-circuit hv side, as, if we short-circuit hv side, V of hv side essentially falls to zero and since VI(KVA power)=constant, so the hv current will be very high(compared to low rated current on hv side), and will burn the winding.

When short-circuiting lv side, the current also increases but this increase does not burn winding due to low rated V and high rated I (You can consider the example of 220/11V)on lv side. So,SC test is performed on hv side while shorting the lv side.

Also SC test can be performed on either sides for small transformer rating. The above care must be taken for big transformer(High KVA rating)..

delta modulation refers to the procedure of encoding and thereby transmitting only the difference between consecutive samples instead of sending each of the samples themselves. This method is useful only when the vaiation in the amplitude of the signal is small, otherwise, it leads to a phenomenon called "slope overload".

Pulse code modulation is the procedure where each of the levels of an analog signal is assigned a value closest ro a quantizer level used to quantize the signal...


Another method of PCM that can be confused with Delta Modulation is the D(ifferential)PCM. Here, the difference between the signals is encoded based on its magnitude..

Net diffusion means the total diffusion due to both holes & electrons .