I am trying to make a thermo-electric generator for a school project, and I need a voltage regulator to keep the USBA output at a constant 5 V. However, I have some step-up boost converter modules at home, and would like to use these.

A few sources said that using a buck-boost converter (4.5 V - 40 to 5 V) would work. Here, they use 8-10 TEC plates. If I use fewer TEC plates to keep the voltage around 3.5 V, then would a step-up converter work too, even if the voltage would fluctuate?

  • \$\begingroup\$ The TEC plates should be connected in series. \$\endgroup\$ Dec 22, 2022 at 21:02
  • \$\begingroup\$ have learned from a few sources that using a step-down converter (4.5v - 40v) would work <-- that's a step up converter. \$\endgroup\$
    – Andy aka
    Dec 22, 2022 at 21:03
  • \$\begingroup\$ no what I mean is 4.5v - 40v to 5v @Andyaka \$\endgroup\$ Dec 22, 2022 at 21:04
  • \$\begingroup\$ Well a step-down (buck) converter can't take in 4.5 V and output 5 V. For that input range (4.5 V to 40 V) you would need a non-inverting buck-boost converter to output 5 V. \$\endgroup\$
    – John D
    Dec 22, 2022 at 21:13
  • \$\begingroup\$ Fixed, thank you, I got confused \$\endgroup\$ Dec 22, 2022 at 21:18

1 Answer 1


A linear regulator is a device to take a varying input voltage as input, and give a constant voltage output, even though the current demanded by the load may vary. There are important caveats: the output voltage is LESS than the input, always, and current will have some practical maximum. These devices still obey Ohm's Law! If you like, you can think of them as "resistors that change their value automatically to keep output voltage constant". They do this by using transistors, which together with diodes, are the most fundamental types of "active component" (semiconductors). You will need to have a decent understanding of these to get much further. Linear regulators are not that efficient - they just burn off excessive power as heat (because they operate basically as "smart resistors"). These devices usually have three terminals - in, out, ground.

A buck regulator is another type of voltage regulator which uses a "switching" mechanism to do the same as a linear regulator, but in a much more efficient way. They do not have to burn power to adjust output voltage (at least, very little) - they use a "feedback" mechanism to keep it constant. (When you study amplifier circuits you will come across feedback a lot.)

There are also boost regulators, which can give out more voltage than they get in! How? using special properties of diodes, transistors, capacitors and inductors. When you understand the more basic elements well, you will be well placed to study this. Until then, a rough idea of what (buck and boost) converters do is enough.


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