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Thursday, September 1, 2011

Basic: Source DC - DC


1 - Basics of electricity
1. Atomic Structure:To understand the current nature we know that ( knowledge of high school ) all the elements are constructed from atoms and each atom of a substance is composed of two parts 

- one nucleus in the middle of the positively charged particles called protons and neutral particles called neutrons. 
- The Electron (e) carry negative charges moving around the nucleus. 
- Normal atoms status electrically neutral means of Proton nuclear electrons outside but when external factors such as pressure, temperature, static friction, the effects of magnetic fields .. e is the electron in the outermost layers can be separated from the orbit to become the free electrons. 
- When an atom loses one or more electronic, we are missing electrons and become positive ions and vice when an atom receives one or several electron, they become negative ions.
2. The nature of current and current direction.
When the electron concentration at high densities on the effects they produce charged 
- current is the flow of charged particles such as electron, ion. 
- Afternoon current is convention went from positive to negative (as opposed to the motion of electrons - from negative to positive)
3. The effects of electrical currents:
When a current flows through the wire as the following experiments:
We see that the electric current generated a magnetic field to deflect around the magnet, when the reverse electric field also redirect => do magnet deflection in the opposite direction. 
- Current flowing through the bulb as light bulbs and heat Siang 
- Current flowing through the motor rotates the rotary engine generates mechanical energy 
- When we load the batteries for the battery plates are changed and the current effects of energy ..
Such currents have the effect of the thermal effects, effects on function, the effects of magnetic and chemical effects on performance.
2 - The current and DC voltage
1. Amperage:
A quantity characteristic of the current strength or specific number of electrons passing through the conductor cross section per unit time - signs that I 
- DC current is flow in a certain direction from positive to negative by convention, or unidirectional flow of free electrons.
The unit of the ampere amperage and the multiples:
  • Kilo Ampere Ampere = 1000
  • Mega Ampere Ampere = 1000.000
  • Mili Ampere = 1 / 1000 ampere
  • Micro = Ampe Ampe 1/1000.000
2. Voltage:
When the density of the electrons are concentrated at two points A and B if you connect a wire from A to B will flow out of the area from where a high density into the densely low, so we call two points A and B have different voltage and the voltage difference is the voltage. 
- The voltage at point A is called U A
- The voltage at point B is called U B . 
- voltage difference between points A and B is called the voltage U AB
AB = U A - U B
- Unit of voltage Vol is denoted by U or E units have multiple voltage is
  • Vol Kilo (KV) = 1000 Vol
  • Vol Mili (mV) = 1 / 1000 Vol
  • Micro 1/1000.000 Vol = Vol
The voltage can be compared to an average height of the water, if water has two different heights, when connecting a pipe will have water flowing from high to average below normal, while two are high in water together, there is no water flowing through pipes. Electric current is the same if the two points with voltage deviation Rachel generates electric current through wires connected to two points from the high voltage to low voltage and if two points are equal, the line voltage in the wire will = 0
3 - The fundamental law
1. Ohm's Law
Ohm's Law is the law important to remember that we need to think
Amperage in the circuit proportional to the voltage at both ends of the circuit and inversely proportional to the resistance of the circuit there.
Formula: I = U / R which
  • I is amperage, measured in ampere (A)
  • U is the voltage at both ends of the circuit, equal to Vol (V)
  • R is the resistance of the circuit, calculated by holding
2. Ohm's Law to the circuit 
The circuit in series:
In one more resistor circuits connected in series, the voltage at both ends of the circuit by the total pressure drop over the resistor.
  • As the diagram on the U = U1 + U2 + U3
  • As we have laws holding U1 = I1 x R1, U2 = I2 x R2, 
    U3 = I3 x R3, but the circuit is connected in series I1 = I2 = I3
  • Voltage drop on resistors => proportional to the resistance. The parallel circuit in the circuit has many resistors in parallel, the amperage of the sum of current through the resistance and pressure drop on the resistors is the same:

  • Circuit is U1 = U2 = U3 = E
  • I = I1 + I2 + I3 = U1 and I2 x I1 x R1 = R2 = R3 I3 x
  • Amperage inversely proportional to the resistance.
3. Power and Power: 
* Power.
When current flows through devices such as light bulb => make light bulbs, running through the motor => such as the rotary engine has generated the current. The electrical power is called, denoted as W, in fact we often use Wh, KWh (Kilo watt hour)
The power equation is:
W = U x I xt
  • In which W is the power measured in June (J)
  • Voltage U is equal to Vol (V)
  • I is current measured in ampere (A)
  • t is time in seconds (s)
* Power.
The power of the electric power is consumed in a second, the capacity is calculated by the formula
P = W / t = (U. I. T) / t = U. I
According to the law have held P = UI = U 2 / R = RI 2

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