Linear regulator Wikipedia. In electronics, a linear regulator is a system used to maintain a steady voltage. The resistance of the regulator varies in accordance with the load resulting in a constant output voltage. The regulating device is made to act like a variable resistor, continuously adjusting a voltage divider network to maintain a constant output voltage and continually dissipating the difference between the input and regulated voltages as waste heat. By contrast, a switching regulator uses an active device that switches on and off to maintain an average value of output. Games That Use A Dance Pad For Kids here. Because the regulated voltage of a linear regulator must always be lower than input voltage, efficiency is limited and the input voltage must be high enough to always allow the active device to drop some voltage. Linear regulators may place the regulating device in parallel with the load shunt regulator or may place the regulating device between the source and the regulated load a series regulator. Voltage Regulator IC is a member of 78xx series of fixed linear voltage regulator ICs. Description, Pinout and PDF Datasheet of 7805 IC. Microcontrollers areonechipcomputersdesignedtocontrolotherequipment, and almost all electronic equipment now uses them. The average American home now contains about. Simple linear regulators may only contain a Zener diode and a series resistor more complicated regulators include separate stages of voltage reference, error amplifier and power pass element. Because a linear voltage regulator is a common element of many devices, integrated circuit regulators are very common. Linear regulators may also be made up of assemblies of discrete solid state or vacuum tube components. OvervieweditThe transistor or other device is used as one half of a potential divider to establish the regulated output voltage. The output voltage is compared to a reference voltage to produce a control signal to the transistor which will drive its gate or base. With negative feedback and good choice of compensation, the output voltage is kept reasonably constant. Linear regulators are often inefficient since the transistor is acting like a resistor, it will waste electrical energy by converting it to heat. In fact, the power loss due to heating in the transistor is the current multiplied by the voltage difference between input and output voltage. RegulatedPowerSupplyCircuit.GIF' alt='7805 Power Supply Pdf' title='7805 Power Supply Pdf' />The same function can often be performed much more efficiently by a switched mode power supply, but a linear regulator may be preferred for light loads or where the desired output voltage approaches the source voltage. In these cases, the linear regulator may dissipate less power than a switcher. The linear regulator also has the advantage of not requiring magnetic devices inductors or transformers which can be relatively expensive or bulky, being often of simpler design, and cause less electromagnetic interference. Some designs of linear regulators use only transistors, diodes and resistors, which are easier to fabricate into an integrated circuit, further reducing their weight, footprint on a PCB, and price. All linear regulators require an input voltage at least some minimum amount higher than the desired output voltage. That minimum amount is called the dropout voltage. For example, a common regulator such as the 7. V, but can only maintain this if the input voltage remains above about 7. Power Supply Pdf File' title='7805 Power Supply Pdf File' />V, before the output voltage begins sagging below the rated output. Its dropout voltage is therefore 7. Harvest Moon Another Wonderful Life Gamecube Iso. V 5. V 2. V. When the supply voltage is less than about 2. V above the desired output voltage, as is the case in low voltage microprocessor power supplies, so called low dropout regulators LDOs must be used. When the output regulated voltage must be higher than the available input voltage, no linear regulator will work not even a Low dropout regulator. In this situation, something like a switched mode power supply of the boost type or a charge pump must be used. Most linear regulators will continue to provide some output voltage approximately the dropout voltage below the input voltage for inputs below the nominal output voltage until the input voltage drops significantly. Linear regulators exist in two basic forms shunt regulators and series regulators. Most linear regulators have a maximum rated output current. This is generally limited by either power dissipation capability, or by the current carrying capability of the output transistor. ConsumablesReplacement Parts for 780508 No. Fits Description 7805L2 780508 Wheel kit includes four wheels, inserts instructions 7806L1. Shunt regulatorseditThe shunt regulator works by providing a path from the supply voltage to ground through a variable resistance the main transistor is in the bottom half of the voltage divider. The current through the shunt regulator is diverted away from the load and flows uselessly to ground, making this form usually less efficient than the series regulator. It is, however, simpler, sometimes consisting of just a voltage reference diode, and is used in very low powered circuits where the wasted current is too small to be of concern. This form is very common for voltage reference circuits. A shunt regulator can usually only sink absorb current. Series regulatorseditSeries regulators are the more common form they are more efficient than shunt designs. The series regulator works by providing a path from the supply voltage to the load through a variable resistance, usually a transistor in this role it is usually termed the series pass transistor it is in the top half of the voltage divider the bottom half being the load. The power dissipated by the regulating device is equal to the power supply output current times the voltage drop in the regulating device. For efficiency and reduced stress on the pass transistor, designs try to minimize the voltage drop but not all circuits regulate well once the input unregulated voltage comes close to the required output voltage those that do are termed Low Dropout regulators, A series regulator can usually only source supply current, unlike shunt regulators. Simple shunt regulatoreditSimple shunt voltage regulator. The image shows a simple shunt voltage regulator that operates by way of the Zener diodes action of maintaining a constant voltage across itself when the current through it is sufficient to take it into the Zener breakdown region. The resistor. R1 supplies the Zener current IZdisplaystyle Imathrm Z as well as the load current IR2 R2 is the load. R1 can be calculated as R1VSVZIZIR2displaystyle R1frac Vmathrm S Vmathrm Z Imathrm Z Imathrm R2, where VZdisplaystyle Vmathrm Z is the Zener voltage, and IR2 is the required load current. This regulator is used for very simple low power applications where the currents involved are very small and the load is permanently connected across the Zener diode such as voltage reference or voltage source circuits. Once R1 has been calculated, removing R2 will allow the full load current plus the Zener current through the diode and may exceed the diodes maximum current rating, thereby damaging it. The regulation of this circuit is also not very good because the Zener current and hence the Zener voltage will vary depending on VSdisplaystyle Vmathrm S and inversely depending on the load current. In some designs, the Zener diode may be replaced with another similarly functioning device, especially in an ultra low voltage scenario, like under forward bias several normal diodes or LEDs in series. Simple series regulatoreditSimple series voltage regulator. Adding an emitter follower stage to the simple shunt regulator forms a simple series voltage regulator and substantially improves the regulation of the circuit. Iec 62301 Software Download'>Iec 62301 Software Download. Here, the load current IR2 is supplied by the transistor whose base is now connected to the Zener diode.