Glossary of power supplies (1)

Here is some Glossary of power supplies:

Line regulation: How much the load voltage or current changes when the power supply isoperated at varying line voltages throughout a given range. Typically stated as a percentage of the total voltage or current available from the supply. A rating of “0%” would mean perfect regulation.

Load regulation: How much the load voltage or current changes between operating the power supply at no-load and full-load conditions. Typically stated as a percentage of the total voltage or current available from the supply. A rating of “0%” would mean perfect regulation.

Efficiency: Measured in percentage, it indicates the amount of power being output over the amount of power consumed in a system.

EMI: Electromagnetic Interference

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Why is there such a big difference in price between power supplies?

A Related question can be asked about automobiles. Both questions have the same answer: there are many factors at play and a simple answer is probably not possible. Many of the factors are:

Marketer name and reputation
Design of the power supplies
Number and type of competitive units
Certifications (such as safety, EMI, etc.)
Dependability of the design
Quality of components used

One thing to talk about while evaluating a power supply (or any equipment) is the total cost of ownership. Include the cost of yearly calibrations and any estimated losses due to unavailability or having to repair or replace the unit if it fails. Over a decennary or more, these costs can easily pass the original cost of the power supply.

How to measure power supply efficiency ?

If efficiency is significant to you, you will need to evaluate it carefully. For a regular DC power supply operated from the AC line, you will need to measure the input AC power and the DC power being output by the supply as in the following plot:
power supply efficiency

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What is Switching power supplies

Switching power supplies, switched mode power supply, SMPS, is basically an electronic power unit that has a switching regulator. Why we need a switching regulator? The switch mode power supply quickly switches a power transistor between on and off. What is the advantage of this? The main advantage of SMPS is that the switching transistor dissipates little power in the full on phase and the off state. Other advantage is that smaller size and lighter weight (high frequency transformers which have a light weight) and lower heat generation due to higher efficiency.

Brazil UC Mark approval

(1). Introduction
• According to the requirements from Inmetro (Brazilian Accreditation Body), products which need to comply with the Brazilian mandatory certification requirements have to carry the mark of conformity.
• For voluntary and mandatory product certification, TÜV Rheinland works together with UCIEE (União Certificadora), a Brazilian OCP (Product Certification Body) which issues the UC Mark.

(2). Compulsory Certification Products
• Electro medical equipment
• Hazardous location equipment
• Equipment for gas systems (pressure regulators and hoses)
• Electrical strings and cables
• Protective devices, such as circuit breakers and fuses
• Switches, plugs and sockets

(3). Voluntary Certification Products
• Luminaries
• Capacitors and filters
• Household
• Electronic appliances and components
• Alarm systems
• IT equipment

(4). Technical information
• Rated voltage: It varies depending on the city. 110V/60Hz, 220V/60Hz are mostly used.
• Plug: 11 different kinds of plugs. (detailed information is available)

(5).Documents required:
• CB test report together with CB certificates, test reports based on EN standards which are identical to Brazilian standards may be accepted (e.g. TÜV/GS) or test reports according to NBR standards.
• Technical information (Construction drawing, circuit diagram, PCB layout, etc)
• User’s manual: in Portuguese for mandatory products or in Portuguese, Spanish or English for voluntary products.
• Rating label in Portuguese

(6). Factory Inspection
• Mandatory products – factory inspections needs to be performed by UCIEE (Follow up inspections may be performed by TÜV Rheinland)
• Voluntary products – the factory inspections can be performed by TÜV Rheinland.

Linear VS Switching Power Supplies

Historically, the linear regulator was the basic technique of producing a regulated output voltage. It controls by cutting a higher input voltage down to a lower output voltage via linearly controlling the conductivity of a series pass power device in response to changes in its load. This results in a large voltage being placed across the pass unit with the load current flowing through it. This headroom loss makes the linear regulator to only be 30 to 50 percent efficient. That means that for each watt delivered to the load, at the least a watt has to be dissolute in heat. The cost of the heatsink actually makes the linear regulator uneconomical above 10 watts for small applications. Below that point, however, they are cost effective in step-down applications.

The switching regulator operates on the power devices in the full-on and cutoff states. This then results in either large currents being passed through the power devices with a low “on” voltage or no current flowing with high voltage across the device. This results in a much lower power being dissipated within the supply. The common switching power supply presents efficiencies of between 70 to 90 percent, no matter the input voltage.

Higher levels of integration have driven the cost of switching power supplies down which makes it an attractive choice for output powers greater than 10 watts or where multiple outputs are desired.

What kinds of power point adapter you need?

universal socket converter

If you’re moving away form your domestic or area of the world and then chances are that yes, you need.

Power socket have various kinds of shapes in different regions of the world and you may require an adaptor to connect the shape of your power plugs to the shape of the electric outlet in the area of the world you’re going to.

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