Saturday, December 3, 2022

# Tutorial: Buck Converter vs. Linear Voltage Regulator

In this video author is comparing in practice a buck converter with LM7805 linear voltage regulator. Here is the showdown buck converter vs linear voltage regulator.

In the video:

• Why & when you should use Buck converters?
• Advantages of linear voltage regulators
• Disadvantages of linear voltage regulators
• How to use linear voltage regulator?
• Where is buck converter used?
• Availability of Buck converters.
• Nomenclature with voltage regulators,
• How to use buck converters?
• Comparison of their usage,
• Testing both under loads for long time,
• Drawbacks of buck converters

## What you learn from the comparison:

• Linear voltage regulator (78xx) use a lot more voltage compared to buck converter.
• Linear voltage converter heats up a lot to dissipate extra current,
• It switches off after heating up, and switches back on again.
• It consumes a lot more power compared to buck converter,
• Buck converter can provide variable output (by varying the potentiometer), whereas, a linear voltage regulator is stuck at only 1 output.

### There are 2 mistakes in the video:

1. 5:02 – 5:08 – correct calculations should be: (12V – 5V) x 0.42A = 2.94W
2. 5:17 – 5:23 – correct calculations should be: (12V – 5V) x 0.22A = 1.54W

#### Courtesy: ElectronFun.com

1. Hi, buck converters are really cool, but they generate such amount of noise , my last project include 4 pots conected to 4 ADC ports and they could’t get stable , values are always floating 10 to 15% of real value. The only solution was power te circuit with an 7805 3Amps in TO3 case with an huge heatsink, stabilizating at 50ºC . My question is : isn’t there an efecience way to eliminate this noise ? Thank you

2. Rui Barroso there are many ways
1) Using a low ESR capacitor or connect parallel capacitances instead of one big one at the output ( tantalum caps have low ESR )
2) Linear regulators have better regulation and noise performance but aren’t efficient when then there is a lot of difference between vin and vout, so you have to use a combination of buck and linear regulator ( low dropout regulator :LDO).
3) check the range of current drawn from the supply and choose an LDO whose output is fairly constant over that range like less than 1%

• Hi Giselle Freude, the video is present on the page. Kindly refresh the page or check your browser flash settings.