Talking about Linear Regulated Power Supply
Until the 1970s, linear regulators were the power source of choice for converting alternating current (AC) to regulated direct current (DC) for electronic equipment. Although this power supply type is not commonly used today, it is still the best choice for applications requiring minimal noise and ripple.
how they work
The main component that allows the linear regulator to function is the steel or iron transformer. This converter provides two functions:
1. It acts as a barrier separating the high voltage AC input from the low voltage DC input, thereby filtering out any noise entering the output voltage.
2. It reduces the AC input from 115V/230V to about 30V, which can then be converted to a stable DC voltage.
The AC voltage is first stepped down by a transformer and then rectified by several diodes. It is then smoothed to a low DC voltage by a pair of large electrolytic capacitors. This low DC voltage is then regulated to a regulated output voltage using transistors or integrated circuits
Preferred Apps
Linear regulators are known for their inefficiency and large size, but they do provide noise-free output voltages. This makes them ideal for any device requiring high frequency and low noise, such as:
1. Control circuit
2. Low noise amplifier
3. Signal Processor
4. Automation and laboratory testing equipment
5. Data Acquisition Sensors and Circuits
Advantage
Simple application. Linear regulators can be implemented as a whole package and added to a circuit with only two additional filter capacitors. This makes it easy for engineers of any skill level to plan and design from scratch.
low cost. If your device requires less than 10W of power output, components and manufacturing costs are much lower compared to switching power supplies.
Low noise/ripple. Linear regulators have very low output voltage ripple and high bandwidth. This makes them ideal for any noise-sensitive application, including communications and radio equipment.
disadvantage
Flexibility is limited. Linear regulators can only be used for step-down voltages. For AC-DC power supplies, a transformer with rectification and filtering functions needs to be placed before the linear power supply, which will increase the overall cost and effort.
limited output. Linear regulated power supplies provide only one output voltage. If you need more, you'll need to add a separate linear regulator for each desired output.
Poor efficiency. Due to heat dissipation, the efficiency of an average linear regulator device is between 30%-60%. It also requires the addition of a heatsink, which increases the size and weight of the device
