Step-down A converter where output voltage is lower than the input voltage (such as a buck converter). Step-up A converter that outputs a voltage higher than the input voltage (such as a boost converter). Continuous current mode Current and thus the magnetic field in the inductive energy storage never reaches zero. Discontinuous current mode. Product Title Watts Step Up-Down Voltage Converter THGUD. Average rating: 5 out of 5 stars, based on 1 reviews 1 ratings. Current Price $ $ Mains electricity (as it is known in the UK and some parts of Canada; US terms include utility power, power grid, domestic power and wall power;  in much of Canada it is known as hydro) is the general-purpose alternating-current (AC) electric power supply. It is the form of electrical power that is delivered to homes and businesses, and it is the form of electrical power that.
Single-phase or three-phase power is most commonly used today, although two-phase systems were used early in the 20th century. Foreign enclaves, such as large industrial plants or overseas military bases, may have a different standard voltage or frequency from the surrounding areas. Some city areas may use standards different from that of the surrounding countryside e. Regions in an effective state of anarchy may have no central electrical authority, with electric power provided by incompatible private sources.
Direct current DC has been almost completely displaced by alternating current AC in public power systems, but DC was used especially in some city areas to the end of the 20th century. Industrial plants with three-phase power will have different, higher voltages installed for large equipment and different sockets and plugs , but the common voltages listed here would still be found for lighting and portable equipment.
Electricity is used for lighting, heating, cooling, electric motors and electronic equipment. Estimated US residential electricity consumption by end use, for the year . The other categories are typically AC applications and usually have much more restricted input ranges. Any current perceived weakness is generally a result of cost reduction and market forces rather than any fundamental technical difficulties.
Where opportunities do exist they are often for specific parts of the overall load and often small parts in terms of total demand. In many countries, household power is single-phase electric power , with two or three wired contacts at each outlet.
Neutral and line wires carry current and are defined as live parts. Various earthing systems are used to ensure that the ground and neutral wires have zero voltage with respect to earth, to prevent shocks when touching grounded electrical equipment. In some installations, there may be two line conductors which carry alternating currents in a single-phase three-wire. Small portable electrical equipment is connected to the power supply through flexible cables these exist with either two or three insulated conductors terminated in a plug , which is inserted into a fixed receptacle socket.
Larger household electrical equipment and industrial equipment may be permanently wired to the fixed wiring of the building. For example, in North American homes a window-mounted self-contained air conditioner unit would be connected to a wall plug, whereas the central air conditioning for a whole home would be permanently wired. Larger plug and socket combinations are used for industrial equipment carrying larger currents, higher voltages, or three phase electric power.
These are often constructed with tougher plastics and possess inherent weather-resistant properties needed in some applications.
Circuit breakers and fuses are used to detect short circuits between the line and neutral or ground wires or the drawing of more current than the wires are rated to handle overload protection to prevent overheating and possible fire. These protective devices are usually mounted in a central panel—most commonly a distribution board or consumer unit—in a building, but some wiring systems also provide a protection device at the socket or within the plug. Residual-current devices , also known as ground-fault circuit interrupters and appliance leakage current interrupters, are used to detect ground faults —flow of current in other than the neutral and line wires like the ground wire or a person.
When a ground fault is detected, the device quickly cuts off the circuit. A distinction should be made between the voltage at the point of supply nominal voltage at the point of interconnection between the electrical utility and the user and the voltage rating of the equipment utilization voltage.
This allows for the voltage drop between equipment and supply. Power distribution system voltage is nearly sinusoidal in nature. Voltages are expressed as root mean square RMS voltage. Voltage tolerances are for steady-state operation. Momentary heavy loads, or switching operations in the power distribution network, may cause short-term deviations out of the tolerance band and storms and other unusual conditions may cause even larger transient variations.
In general, power supplies derived from large networks with many sources are more stable than those supplied to an isolated community with perhaps only a single generator.
The choice of supply voltage is due more to historical reasons than optimization of the electric power distribution system—once a voltage is in use and equipment using this voltage is widespread, changing voltage is a drastic and expensive measure. Minimum wire size for hand-held or portable equipment is usually restricted by the mechanical strength of the conductors.
National electrical codes prescribe wiring methods intended to minimize the risk of electric shock and fire. Three-phase systems can be connected to give various combinations of voltage, suitable for use by different classes of equipment.
Large loads are connected for the higher voltage. Other three-phase voltages, up to volts, are occasionally used for special-purpose systems such as oil well pumps. Equipment with the exception of filament bulbs used in these countries is designed to accept any voltage within the specified range. The boundary between the two regions contains four back-to-back high-voltage direct-current HVDC substations which interconnect the power between the two grid systems; these are Shin Shinano , Sakuma Dam , Minami-Fukumitsu , and the Higashi-Shimizu Frequency Converter.
To accommodate the difference, frequency-sensitive appliances marketed in Japan can often be switched between the two frequencies. The world's first public electricity supply was a water wheel driven system constructed in the small English town of Godalming in In Edison patented a three—wire distribution system to allow DC generation plants to serve a wider radius of customers to save on copper costs. Both voltages are available on the three wires two "hot" legs of opposite phase and one "neutral" leg.
The company was able to offset the cost of converting the customer's equipment by the resulting saving in distribution conductors cost. In the first decade after the introduction of alternating current in the US from the early s to about a variety of different frequencies were used, with each electric provider setting their own, so that no single one prevailed. To maintain the voltage at the customer's service within the acceptable range, electrical distribution utilities use regulating equipment at electrical substations or along the distribution line.
At a substation, the step-down transformer will have an automatic on-load tap changer, allowing the ratio between transmission voltage and distribution voltage to be adjusted in steps. For long several kilometres rural distribution circuits, automatic voltage regulators may be mounted on poles of the distribution line.
These are autotransformers , again, with on-load tapchangers to adjust the ratio depending on the observed voltage changes. Since these taps are not automatically controlled, they are used only to adjust the long-term average voltage at the service and not to regulate the voltage seen by the utility customer. DC-to-DC techniques that use transformers or inductors work at much higher frequencies, requiring only much smaller, lighter, and cheaper wound components.
Consequently these techniques are used even where a mains transformer could be used; for example, for domestic electronic appliances it is preferable to rectify mains voltage to DC, use switch-mode techniques to convert it to high-frequency AC at the desired voltage, then, usually, rectify to DC.
The entire complex circuit is cheaper and more efficient than a simple mains transformer circuit of the same output. DC-DC converter is widely used in the DC microgrid applications for different voltage level applications. Practical electronic converters use switching techniques.
Switched-mode DC-to-DC converters convert one DC voltage level to another, which may be higher or lower, by storing the input energy temporarily and then releasing that energy to the output at a different voltage. The storage may be in either magnetic field storage components inductors, transformers or electric field storage components capacitors.
This conversion method can increase or decrease voltage. Fast semiconductor device rise and fall times are required for efficiency; however, these fast transitions combine with layout parasitic effects to make circuit design challenging. Efficiency has improved since the late s due to the use of power FETs , which are able to switch more efficiently with lower switching losses at higher frequencies than power bipolar transistors , and use less complex drive circuitry.
Another important improvement in DC-DC converters is replacing the flywheel diode by synchronous rectification  using a power FET, whose "on resistance" is much lower, reducing switching losses. Before the wide availability of power semiconductors, low-power DC-to-DC synchronous converters consisted of an electro-mechanical vibrator followed by a voltage step-up transformer feeding a vacuum tube or semiconductor rectifier, or synchronous rectifier contacts on the vibrator.
Most DC-to-DC converters are designed to move power in only one direction, from dedicated input to output. However, all switching regulator topologies can be made bidirectional and able to move power in either direction by replacing all diodes with independently controlled active rectification.
A bidirectional converter is useful, for example, in applications requiring regenerative braking of vehicles, where power is supplied to the wheels while driving, but supplied by the wheels when braking. Although they require few components, switching converters are electronically complex.
Converters are also available as complete hybrid circuit modules, ready for use within an electronic assembly. Linear regulators which are used to output a stable DC independent of input voltage and output load from a higher but less stable input by dissipating excess volt-amperes as heat , could be described literally as DC-to-DC converters, but this is not usual usage. The same could be said of a simple voltage dropper resistor, whether or not stabilised by a following voltage regulator or Zener diode.
There are also simple capacitive voltage doubler and Dickson multiplier circuits using diodes and capacitors to multiply a DC voltage by an integer value, typically delivering only a small current. Transformer-based converters may provide isolation between input and output. In general, the term DC-to-DC converter refers to one of these switching converters. These circuits are the heart of a switched-mode power supply. Many topologies exist.
This table shows the most common ones. Magnetic DC-to-DC converters may be operated in two modes, according to the current in its main magnetic component inductor or transformer :. A converter may be designed to operate in continuous mode at high power, and in discontinuous mode at low power.
The half bridge and flyback topologies are similar in that energy stored in the magnetic core needs to be dissipated so that the core does not saturate. Although MOSFET switches can tolerate simultaneous full current and voltage although thermal stress and electromigration can shorten the MTBF , bipolar switches generally can't so require the use of a snubber or two.
High-current systems often use multiphase converters, also called interleaved converters. Many laptop and desktop motherboards include interleaved buck regulators, sometimes as a voltage regulator module. Specific to these converters is that the energy flows in both directions of the converter.
These converters are commonly used in various applications and they are connected between two levels of DC voltage, where energy is transferred from one level to another. Switched capacitor converters rely on alternately connecting capacitors to the input and output in differing topologies. For example, a switched-capacitor reducing converter might charge two capacitors in series and then discharge them in parallel.
Because they operate on discrete quantities of charge, these are also sometimes referred to as charge pump converters. They are typically used in applications requiring relatively small currents, as at higher currents the increased efficiency and smaller size of switch-mode converters makes them a better choice.
A motor-generator set, mainly of historical interest, consists of an electric motor and generator coupled together. A dynamotor combines both functions into a single unit with coils for both the motor and the generator functions wound around a single rotor; both coils share the same outer field coils or magnets. The entire rotor and shaft assembly is smaller in size than a pair of machines, and may not have any exposed drive shafts.
Motor-generators can convert between any combination of DC and AC voltage and phase standards. Large motor-generator sets were widely used to convert industrial amounts of power while smaller units were used to convert battery power 6, 12 or 24 V DC to a high DC voltage, which was required to operate vacuum tube thermionic valve equipment.
For lower-power requirements at voltages higher than supplied by a vehicle battery, vibrator or "buzzer" power supplies were used. The vibrator oscillated mechanically, with contacts that switched the polarity of the battery many times per second, effectively converting DC to square wave AC, which could then be fed to a transformer of the required output voltage s.
A further means of DC to DC conversion in the kilowatts to megawatts range is presented by using redox flow batteries such as the vanadium redox battery. DC-to-DC converters are subject to different types of chaotic dynamics such as bifurcation ,  crisis , and intermittency. From Wikipedia, the free encyclopedia.