I am trying to power 5 servo motors from a 5v 7805 regulator with decoupling capacitors. The source is a 9.6v rc battery. Since the servos require 5v I am trying to get 5v to them from the battery hence the regulator but in practice only 3 servos can function at one time and are still causing the regulator to get incredibly hot, connecting any more will stop all of them from working. Since the 7805 can supply little current relative to what I want, What can be an alternative and more efficient way to power these servos with the 9.6v battery I have?
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3\$\begingroup\$ Possible duplicate of My linear voltage regulator is overheating very fast \$\endgroup\$– C_ElegansCommented Mar 17, 2018 at 23:35
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2\$\begingroup\$ There are drop in regulators like the OKI-78SR series that directly replace the 7805 and provide 1.5A of output current with very very little heat. power.murata.com/data/power/oki-78sr.pdf \$\endgroup\$– Dean FranksCommented Mar 17, 2018 at 23:45
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2 Answers
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There are two entirely different questions here.
First, is it possible to drive more servos using 7805s? And how to keep the regulators from getting hot?
Yup. Use one 7805 per servo, and buy some heat sinks. I've seen 5 volt, 75 amp power supplies which used linear regulators. With really hefty heat sinks and forced air cooling.
Second, what other ways are there to produce 5 volts?
In a word, switching. Since this site does not allow specific product recommendations, Google "5 volt switching regulator". Of course, you'll need to know more about what you're doing, since you'll need to ensure that switching noise does not cause problems, but you'll get much higher efficiencies.
answered Mar 17, 2018 at 23:41
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As you have used the word "regulator" in "causing the regulator to get incredibly hot", rather than the word "heatsink" this leaves open the possibilty that you just have a regulator IC with no heatsink.
If this is the case, yes it will get incredibly hot. a 7805 should be bolted to a heatsink. i.e. a piece of aluminium
