Senin, 30 Januari 2012

PULSE Sources

PULSE Sources

This type of source can be either a voltage or a current source. We often use it as a stimulus for transient response simulation of a circuit. It should never be used in a frequency response study because the model assumes it is in the time domain. The designation of the pulse source starts as any other independent source; i.e., the part name must begin with the letter V (for voltage) or I (for current). This is followed by the node names. Then, instead of "DC" or "AC," we use the keyword "PULSE" followed by the necessary parameter list. Items in the parameter list may be separated by spaces or commas. An example of a pulse type of voltage source follows:

The parameters for the pulse (to be entered in the order given) are:

V1 is the value when the pulse is not "on." This can be zero or negative as required. For a pulsed current source, the units would be "amps" instead of "volts."
V2 is the value when the pulse is fully turned on. This can also be zero or negative. (Obviously, V1 and V2 should not be equal.) Again, the units would be "amps" if this were a current pulse.
Td is the time delay. The default units are seconds. The time delay may be zero, but not negative.
Tr is the rise time of the pulse. PSpice allows this value to be zero, but zero rise time may cause convergence problems in some transient analysis simulations; i.e., there is a very good reason for the existence of this parameter. The default units are seconds.
Tf is the fall time in seconds of the pulse. See note on Tr before setting this to zero.
Tw is the pulse width. This is the time in seconds that the pulse is fully on.
Period is the total time in seconds of the pulse. Be aware that the pulse repeats if the simulation time exceeds the period.

Minggu, 29 Januari 2012

Zener Voltage

Zener Voltage
Zener diode is a diode that has the characteristics of the channel the electrical current flowing in the opposite direction when the applied voltage overshoot "breakdown voltage" (breakdown voltage) or "Zener voltage". This is different from ordinary diode which only transmits electrical current to one direction.

Diodes usually will not drain the electrical current to flow in the opposite if the reverse-biased (reverse-biased) below the breakdown voltage. If the operating voltage exceeds the limit, regular diode will be damaged because of excess electrical current that causes heat. However, this process is reversible if it is done within your limits. In the case of rationing-forward (in the direction of the arrow), this diode will provide voltage drop (voltage drop) of about 0.6 volts for a normal silicon diode. The voltage drop depends on the type of diode used.
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Minggu, 22 Januari 2012

semiconductor components

The simplest semiconductor components, it consists of two (2) the cathode and anode electrodes.

End of the body diode is usually given a marked, a bracelet or a point, which indicates the location of the cathode.

Diodes can only DC current flowing in the direction of course, in the reverse direction DC current will not flow. If the silicon diode is energized AC currents of electricity, then that flow only in one direction only so that the flow of DC current output diode.

When given the potential positive anode and negative cathode, said diode is forward biased and when given the contrary, is said to be reverse biased diode. On the forward bias, the difference between the cathode and the anode voltage is called threshold voltage or knee voltage. Large voltage depends on the type of diode, can be 0.2V, 0.6V and so on.

When the diodes are reverse biased (which vary depending on supply voltage voltagenya) reverse voltage is called voltage. This reverse voltage must not exceed a certain price, this price is called the breakdown voltage, eg 50V sebasar 1N4001 diode type.

Eg type germanium diodes type 1N4148 or 1N60 when given forward bias can forward radio frequency vibrations, and when a forward bias is removed, will block the radio frequency vibrations. The existence of these properties, diode types are used for switches.

Zener diode is a diode which has the property that rollovers are very stable voltage, this voltage is called the zener voltage. Above the zener voltage, this diode will deliver electricity in two directions. This diode is used as a voltage stabilizer or voltage regulator. These diodes form a diode as usual, the difference can be seen only from the type that is written on bodynya and zener voltage seen at vademicum.

In the market there are different types of resistors, can be classified into two kinds of fixed resistors is the resistor value detainees remains and anyone can diaturatur by hand, there is also a change in the value of prisoners is set automatically by light or by temperature.

Resistor color code is usually written in roundabout budaran shaped bracelet or can be color. The units used are OHM (Ω). Unless the amount of resistance, a resistor is characterized by tolerance, also written in the form of bands of color after the sign of resistance.

The next parameter is the magnitude of the resistor the maximum power allowed to pass through. Regarding the maximum power is not supplied by the manufacturer's mark but only seen from demensinya only. Resistors there who have the ability 1 / 8 Watt, 1 / 4 Watt, 1 / 2 Watt, 1 Watt, 2 Watt, 5 Watt, and so on.

The color code for tolerance is is as follows:

1 percent = Chocolate
2 percent = Red
5 percent = Gold
10 percent = Silver

Material for wire-wound resistors may be used or can be prisoners with carbon. With the coil wire resistance, then, unless the resistance, inductance will also give you a little. At this time the use of carbon resistors are not widely available in the market.
Variable Resistor (VR)

Resistor value of this type can be set by hand, if arrangements can be made at any time by the operator (there is a key regulator) is called a potentiometer and an arrangement made with a screwdriver called a trimmer potentiometer (trimpot). Prisoners in the potentiometer can be made from carbon and there are also made from coils of wire called a wirewound potentiometer. For use in high voltage usually preferred wirewound types.
Sensitive Resistor Temperature and Light Sensitive Resistors

Thermistor resistance value depends on the temperature. There are two types of NTC (negative temperature coefficient) and PTC (positive temperature coefficient). NTC little resistance when hot and cold getting bigger. Instead PTC little resistance when cold and expand when hot.
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