Electrical Engineering

A welding transformer uses the alternating current supplied to the welding shop at a high voltage to produce the low voltage welding power

Thats a good question

A: Depends on the circuitry involved an op amp normally has a 90 Db rejection from variation, Logic gates however are more sensitive to power supply variation for the simple point that triggering points changes which translate in false triggering and the circuits miss behaving

A: Take 115 volts and multiply by 2.82. The frequency does not matter but he voltage does

A: a transformer will follow the rule of input output ratio with no load. As soon as a load is applied there will be changes in the ratio

To size cable the amperage must be known. Use the following equation to find amperage. Amps = kW x 1000/1.73 x volts x pf.

A standard motor's power factor between 10 to 100 HP is .86 to .92.

Amps = 90 x 1000 = 90000/ 1.73 x 440 x .92 = 90000/700 = 128 amps.

Motor feeders have to be rated at 125% of the motor full load amperage. 128 x 125% = 160 amps.

A 2/0 copper conductor with an insulation factor of 75 or 90 degrees C is rated at 175 and 185 amps respectively.

PLC can take both types of inputs. Logic can be written suitably with in the processor software.

a digital multimeter uses similar input circuits to those used in an analog multimeter for the various scales, but uses a dual slope integrating analog to digital converter to get a precise digital value of four or five digits to display. this type of analog to digital converter is slow but very precise, also though slow it is more than fast enough for a human to not perceive the slowness.

Current I = V/R

V = 9V

R = 100ohm

I = 9V/100ohm = 90mA

"If you connected the battery in reverse that will certainly fry the alternator and cause damage to any other polarity sensitive components as well.

The alternator is NOT suposed to spark, it charges by by generating alternating current which is converted to direct current through a diode pack known as the rectifier, and the voltage is regulated by some more electronic wizardry called (amazingly enough) a regulator.

Normally when alternators go wrong the charging warning light will glow, and you will get the wrong readings from your voltmeter (if your car has one)."

transformer max earth fault current

The shop charges a $200 minimum. After that the price is up to the individual artists.

These are a niche market, and the demand is not particularly high. Designing a Gunn or Impatt oscillator is not a trivial exercise, and the biasing is a pain. These designs are generally built by skilled craftsmen and are not suited to mass production. At 24 GHz or below, a GaAs MESFET or PHEMT is much more practical as an active device.

The opening angle of a pyramidal horn antenna is to match the impedance of the horn antenna to that of free space. With this enlargement of the dimension, the velocity of the wave travelling will decrease. This will increase the guide wavelength, which in turn increases the impedance of the horn. This gives an impedance value closer to that of free space there by giving better power transfer.

Yes. Let's look at an example.

A 12 volt system can operate a 12 volt relay coil to actuate the plunger. But when the field of the coil collapses in the instant following when the coil is de-energized, the collapsing field can generate an "inductive kick" that can easily reach several hundred volts.

Relay coils frequently have diodes across their coils to shunt this voltage through the coil and prevent it reaching other parts of the circuit because it is a higher voltage and could damage components.

As a closing note, you're not "getting something for nothing" or generating more energy out of the coil than originally went in. The power in still equals the power out (less any loss). With a properly designed coil utilizing Marko Rodin's configuration, losses are negligible.

A VAR Meter is used to measure Reactive Power in AC Circuits - Pure reactive components dissipate zero power, which makes sense in a DC circuit, as a capacitor passes no DC current and an inductor displaces no voltage. Yet, in an AC circuit, the reactive components "seem" to dissipate power, as current passes through the capacitor and the inductor sees a voltage drop. This counterfeit power is called "reactive power" and is measured not in Watts, but in VARs (Volt-Amps-Reactive). Its mathematical formula symbol is "Q".

A VAR Meter is used to measure Reactive Power in AC Circuits - Pure reactive components dissipate zero power, which makes sense in a DC circuit, as a capacitor passes no DC current and an inductor displaces no voltage. Yet, in an AC circuit, the reactive components "seem" to dissipate power, as current passes through the capacitor and the inductor sees a voltage drop. This counterfeit power is called "reactive power" and is measured not in Watts, but in VARs (Volt-Amps-Reactive). Its mathematical formula symbol is "Q".

Voltage = (current) x (resistance)

Current = (voltage)/(resistance)

Resistance = (voltage)/(current)

Often we want to easily change a resistor value, so we use a variable resistor.

For example, we may want to change the resistor that controls the power sent to a LED, so we can easily make it brighter or dimmer.

Often if we use a variable resistor, there is only a very narrow range that is useful.

Continuing our example, sometimes we use several LEDs, and we use the variable resistor to set them all to the same brightness.

In this case, the resistance range that sets the LED to be twice as bright as the the other LEDs, and the resistance range that sends so much power to the LED that it is permanently destroyed is even less useful.

So we add a fixed resistor in series with the variable resistor -- the fixed resistor sets the minimum net resistance, no matter how we turn the knob on the variable resistor.

In our example, the addition of the fixed resistor allows us to turn the variable resistor throughout its whole range, and the LED gets brighter and dimmer; without that resistor, a certain range of the knob on the variable resistor would allow so much power to go to the LED that it would be destroyed.

A: Transmission lines while there is ceramic insulators providing separation to the phases will have a corona if the insulators are dirty providing small current leakage ionizing the air around it therefore corona effect.

A: Mica is an insulator used extensively in capacitors and hi quality transformers. It has very good temperature coefficient

A; BUFFER is used for isolation, translation of levels and amplification if needed