Power supply#Programmable power supply

As a laboratory power supply, also known as laboratory power supply, power supplies are referred to, which can be used in electronics development, test and service area in the hobby electronics and education universal.

Laboratory power supplies are there depending on the requirements in a very wide variety of designs with one or more fixed or adjustable voltage limits, fixed or adjustable current limits and for different services. Tracking capability lab power supplies can symmetrical output voltages of opposite sign but spend the same amount.

Laboratory power supplies always have a control, at least for the output voltage, often for the output current. They can be designed to with power transformer, rectifier and linear control or as a switching power supply.

Demarcation

Unlike conventional plug or desktop power supplies laboratory power supplies have some typical features:

• The one or more outputs are overload and short -, short-circuit, reverse polarity protection in most cases.
• Certain types of laboratory power supplies can operate as electronic loads, ie the laboratory power supply can accommodate a externally applied power.
• Transient response, ripple and noise of the output voltage (s) are specified.
• A fixed or adjustable current limit is available; it is key differentiator to traditional power supplies: When the set maximum current this laboratory power supplies go on the behavior of a constant voltage source ( with load-dependent current) in the constant current source ( with load-dependent voltage) across. The output voltage is thus lower than the set limit value in the operating range of the constant current control. This can extend to the short circuit, without the instrument is damaged, because the current is maintained at the set value. The graph shows a rather low resistive load ( shallower inclined straight line ) that the current limitation is active, and at a rather high load ( steeper inclined straight line ), the voltage limitation. The adjusting to operating condition results from the intersection of the rectangular network device characteristic with the load characteristic.
• At least with adjustable devices, there are ads for the set or output voltage and output current or the set.
• The connections are standardized, mostly designed for the connection of so-called banana plugs, in laboratory power supplies that can supply voltages above 60 V, they are also performed non-contact generally safe.
• Higher quality laboratory power supplies are adjustable via interfaces such as the IEC 625 bus, or on newer laboratory power supplies using LXI, from a control computer. In some cases they can also carry out independent test sequences, so that the transition to power signal generators is fluid.
• Higher quality laboratory power supplies often have two additional sockets, which are usually labeled " Sense" ( visible in the photo at the bottom of the unit). When connecting the load with the usual two leads for voltage limitation of the built-in controller keeps the temperature measured on the sockets voltage constant. Voltage losses in the plug contacts and leads are not detected and not corrected. But excluding a consumer as a low- resistance measuring means of the additional measurement (sense ) lines in four-wire circuit where the voltage is directly to the load (instead of at the terminals ) measured and kept in a stable manner. In the additional lines no current flows, according to the voltage drop is omitted.

• Power Supply
• Power Electronics