1/2 watt (In theory you could use a "0.27 Watt" resistor, however there would be no safety factory and there is no standard value resistor that size.)
Because that is what you are trying to measure.
This capacitor carries a current of 25,000/690 or 36.2 amps and its impedance (reactance) is 19 ohms. The capacitance is 1/(2.pi.50.19) or 0.000167 Farad, on a 50 Hz system. The time-constant is CR so that if a 20,000 ohm resistor is placed across the capacitor the time-constant is 3.3 seconds. The voltage is reduced by 99% after 5 time-constants or in this case 17 seconds. If the discharge resistor is permanently in circuit it dissipates 690^2 / 20000 or 24 watts.
A capacitor is placed across the supply of a fluorescent lamp circuit to correct the power factor
A capacitor is placed across the supply of a fluorescent lamp circuit to correct the power factor
Some of the more common values are 1/8, 1/4, 1/2, 1 and 2 watts. On PC boards the larger resisters are not placed adjacent to the board but connected into the board above the board using standoffs. This is to let air circulate around the resistor to carry away the heat generated by the resistor. The physical size of the resistor reflects the resistors ability to dissipate the heat which builds up inside the resistor. As the wattage goes up so does the physical size of the resistor. Resistors that dissipate very large amounts of power (watts) are usually wire-wound resistors. Wire-wound resistors can be as high as 100 watts.
It depends on where and how the resistor is placed in a circuit. A string of series resistors will split the voltage across all them depending on their values. All of the resistors in parallel will have the same voltage across all of them no matter what their resistance is.
A: It can be two things one a resistor to limit the current to a safe level and two is a hi resistor placed across the LEDS if placed in series with hi voltage source. That will equalize the leakage current so the string will not fail because of it.
For the individual resistor, the current is constant, regardless of any other resister that's attached to it in parallel. The current that results from all the resistors combined decreases as the resistance of one or more of the resistors increases.
A resistor placed across the power line: I squared R (current x current x resistance) = heat in watts.
Power dissipated in a resistance = E2/R = (100)2/100 = 100 watts.
A capacitor is typically placed across a resistor for the purpose of shunting either the AC component of a current (as in a transistor amplifier) or transient AC 'spikes', and is referred to as a "bypass capacitor".
The power dissipated by a 1-ohm 1/4-watt resistor reaches its rated value when the voltage across it is 1/2 volt. Any more than that, and the resistor's power dissipation rating is exceeded. 12 volts across 1 ohm produces a current of E/R = 12 amperes (as long as the battery can deliver it), and a power dissipation of E2/R = 144 watts. The resistor will smoke, glow, and possibly pop, as it fails catastrophically.
Resistor placed in the emitter lead of a transistor circuit to minimize the effects of temperature on the emitter-base junction resistance.
No such resistor exists. Any resistor placed in parallel with a 6.0 ohm resistor is going to reduce the combined resistance below 6.0 ohms.
The inconvenience of an ammeter is that it needs to be placed in the line in which you want to measure the current; for production circuits, this is often inconvenient or impossible, so usually the current in a circuit is derived by measuring the voltage drop across a resistor.
Resistor values are given in ohms. A value may be selected to deliver a specific current at a given voltage. This is given in what is known as Ohm's Law where: Voltage (V) = Current (A) X Resistance (Ohm) A 12ohm resistor placed across a 12V battery would pass 1Amp of current and put out 12W of heat.
no, your on your own. It depends upon the individual's circumstances, the minimum legal age is 18, so a 17-year old could be placed in a group home if they do not have a acceptable place to live.