What is a laboratory power supply?
A laboratory power supply, also known as a bench power supply, is a device used in laboratory or electronic environments to provide controlled and regulated electrical power to other electronic devices, components or circuits. These power supplies are used to precisely and adjustable supply voltage and current to power and test electronic components, circuits and devices.
Typical features of a laboratory power supply include:
- Adjustable voltage: They allow the output voltage to be adjusted according to the needs of the experiment or project, generally in a wide range.
- Adjustable Current: They offer the ability to adjust the output current to limit it and protect connected devices. So that if there is a fault, such as an increase in current due to an accidental error, no more current passes through the load than that which has been previously adjusted.
- Regulation: Even if there are variations in consumption by the load, the adjusted output voltage does not vary, remaining stable.
- Protection: They usually have protection features, such as short circuit and overload protection, to prevent damage to the devices under test and/or the power supply itself.
- Display: Most laboratory power supplies feature a display or meters that show the output voltage and current in real time.
- Control interfaces: Some modern power supplies offer digital control interfaces that allow output to be adjusted using software or remote devices.
These power supplies are essential in electronics, providing the ability to perform tests and experiments in a controlled and safe manner, as well as facilitating the powering of components and circuits in prototypes and development projects.
What type of laboratory power supplies are there?
There are several types of laboratory power supplies, each with specific characteristics for different applications. In general, the laboratory power supply that is generally used in electronics, like other types of sources and feeders, can be linear or switched.
Linear power supply:
These power supplies use transformers and linear regulators to generate output voltage and current. They offer high precision and low noise interference, but tend to be heavier and less efficient compared to switching power supplies.
Switch Mode Power Supply (SMPS):
Also known as switching power supplies, these use electronic switching to generate the output voltage and current. They are more efficient and compact than linear sources, but can generate more electrical noise and may require additional filtering for noise-sensitive applications.
But functionally we can have the following types of laboratory sources:
Adjustable DC direct current laboratory power supply:
This type of power supply can be linear or switching. And it has the typical features that we listed at the beginning: adjustable voltage and current, indicators displaying the current and voltage provided, along with short circuit, overcurrent and temperature protections. In some cases they may also have control interfaces such as USB, GPIB, RS232, etc.
In turn, we have simple power supplies with a single variable channel, double ones and even three or four variable channels.
When they have 2 or more independent channels, they have other buttons that allow the channels of said source to be arranged in the following ways or modes of operation:
Independent mode: Each of the sources can be regulated independently in both voltage and current in order to have different voltages.
Serial mode: In this case it allows me to obtain a power supply with the same current from each of the power supplies, but the voltage can increase to the sum of the channels. For example it may be useful to obtain a symmetrical power supply or simply increase the maximum output voltage. Normally one of the sources acts as master and the meters associated with said source are those that indicate both voltage and current delivered.
Parallel mode: The output voltage is the same as that delivered by each independent source, but the current delivered increases by the sum of all channels. Normally one of the sources acts as the master and the meter associated with said source is the one that displays both the current and the voltage delivered.
In any case, these three modes of operation of adjustable laboratory sources are quite general and we recommend reading exactly the instruction manual for each one depending on the case.
Programmable power supply:
These supplies allow the user to program and control the output voltage and current through digital interfaces. They are ideal for automated testing applications and computer-controlled experiments. In turn, a programmable power supply can be linear or switched or use both technologies.
Programmable power supplies offer a wide variety of solutions in laboratories, electronic testing and project development. Its ability to control and adjust output voltage and current precisely and programmably. Its possibility of recording all this data, for later analysis and/or making a graph, makes it a versatile tool for numerous tasks.
Generally all these types of power supplies support or have specific communications protocols and/or programs for automation and control of instrumentation and equipment in measurement processes such as SCPI or LabVIEW, which we will explain in more detail below.
High voltage power supplies:
Designed to provide very high voltages, often used in applications such as insulation testing, arcing, or in research into high-voltage electronic devices. You can use linear or switched source technology, or both.
AC alternating current power supplies:
Although laboratory power supplies generally deliver DC direct current, there are others that deliver AC alternating electrical energy. Depending on the frequency of the current delivered to the load, we have fundamentally two types of AC power supplies.
50/60Hz Power Supplies:
Alternating current (AC) power supplies are devices designed to supply electrical power in the form of alternating current, rather than direct current (DC) like conventional laboratory power supplies. These power supplies are primarily used to provide alternating current to devices or equipment that require AC power, such as appliances, lighting systems, electric motors, HVAC systems, and other AC-powered equipment.
AC power supplies are typically designed to provide alternating current at a standard frequency, such as 50 Hz or 60 Hz, and at a specific voltage, such as 110 V, 220 V, or 240 V, depending on geographic region and electrical standards. local. These supplies can come in a variety of shapes and sizes, from small AC adapters used to charge electronic devices to larger, more robust AC power supplies used in industrial applications.
These power supplies allow us to simulate the voltage of the electrical network and we can cause variations so that we can know the functionality of the equipment when the network voltage is not adequate, so that we can know its stability before putting it into operation. the market.
400Hz Power Supplies:
However, the 400 Hz (hertz) frequency is common in the aviation and aeronautics industry for the generation and distribution of electrical power in commercial and military aircraft. Here is more information about 400 Hz power supplies in aviation:
Reason for use in aviation: The choice of 400 Hz as the standard frequency in aviation is due to several reasons. Compared to the conventional 50 Hz or 60 Hz mains frequency used in ground applications, the 400 Hz frequency offers some advantages in terms of weight, size and efficiency for aircraft onboard electrical systems. This is especially important in aviation, where weight and space are critical factors.
Benefits of 400 Hz:
Smaller size and weight: Transformers and electrical components can be more compact and lighter at 400 Hz compared to 50 Hz or 60 Hz, which is crucial in aerospace applications.
Greater efficiency in rotating electrical systems: Electric motors, generators and rotating electrical systems can operate more efficiently at 400 Hz.
Better power quality: Higher frequency can provide better power quality for sensitive electronic devices and avionics systems.
Power Generation: In aircraft, electrical power is generated by generators powered by aircraft engines, known as 400 Hz generators. These generators produce power at 400 Hz which is then distributed throughout the aircraft to power critical and non-critical systems. .
Converters and Distribution: Frequency converters and power distribution units are used to adapt and distribute 400 Hz electrical power to systems that require it. These systems ensure reliable distribution of electrical power throughout the aircraft.
Avionics systems and electrical equipment: The aircraft's navigation systems, communications, lighting, inflight entertainment systems, and other electrical equipment are designed to operate on 400 Hz power.
In summary, 400 Hz power supplies are essential in aviation to provide efficient and reliable electrical power to critical systems and equipment on board commercial and military aircraft. These systems are designed to meet the rigorous safety and performance standards of the aerospace industry and ensure the safe and efficient operation of aircraft.
The choice of a laboratory power supply will depend on the specific needs of the application, such as the required accuracy, voltage and current range, efficiency and available budget. Each type has its advantages and disadvantages, and it is important to select the appropriate one according to the context in which it will be used.
What is SCPI and LabVIEW?
SCPI (Standard Commands for Programmable Instruments) and LabVIEW are two concepts related to the automation and control of instrumentation and equipment in the field of electronics and instrumentation.
SCPI (Standard Commands for Programmable Instruments):
Definition: SCPI is a communication standard that defines a set of commands and syntax conventions used to control and communicate with programmable measuring instruments and test equipment, such as oscilloscopes, multimeters, signal generators, and programmable power supplies.
Purpose: SCPI provides a common language and set of commands that enable engineers and scientists to consistently control, configure, and collect data from a variety of instruments from different manufacturers, facilitating interoperability and automation in a laboratory or environment of tests.
Example: A typical SCPI command might be "SET VOLTAGE 5.0" to set the output voltage of a programmable power supply to 5.0 volts.
LabVIEW:
Definition: LabVIEW (Laboratory Virtual Instrument Engineering Workbench) is a software and systems development environment developed by National Instruments (now part of Keysight Technologies) used for data acquisition, instrumentation control, and system automation.
Purpose: LabVIEW enables engineers and scientists to create custom graphical applications and test systems using an intuitive graphical interface. Users can drag and drop visual elements called "function blocks" to design the control flow and logic of their application.
Applications: LabVIEW is used in a wide variety of fields, such as industrial automation, process instrumentation and control, data acquisition, systems engineering, robotics, and scientific research.
Advantages: LabVIEW is especially useful for creating custom user interfaces and instrumentation control systems. It can integrate with a wide range of measurement and control hardware and devices, including those that use SCPI commands.
In summary, SCPI is a communication standard for controlling programmable measuring instruments and test equipment using text commands, while LabVIEW is a systems development environment that allows the creation of graphical applications and custom control systems, facilitating automation. and interaction with instrumentation, including that using SCPI as a communication protocol. Both are important in the field of automation and control of measurement and test systems.
These two protocols or programs like LabVIEW and SCPI are not exclusive to programmable sources. There may be laboratory power supplies of other types that also
