Low Power Arduino! Power Supply Considerations p1 

+State of Electronics hard to beat the price and simplicity of dc-dc modules like this: www.ebay.com/itm//272041589000

+Lasse Langwadt Christensen yea, those are nice but you've gotta watch the current draw from the resistor feedback network. I'll make a part 2 on DC-DC regulators and explain this as well as test some of these cheap modules

+Kevin Darrah correct, if the not the feedback the quiescent current to run the switcher can easily be in mAs so in systems that spend a significant amount of time in sleep modes using 10's of uA a linear regulator could easily win on efficiency. The most efficient would be to combine the two and only enable the switcher at high current draws

+Lasse Langwadt Christensen Depends what your input is: 5 to 3.3V conversion using LDO's probably wins every time if the regulator has a low quiescen current (not a NCP1117 as often used on arduino) with 66% efficiency. From 12v... hardly. If you're operating from a single lithium cell and you need 5V, however a linear regulator wont do, unless you're using a charge pump. I guess we can have the same discussion when it comes to synchronous versus non synchronous rectification for SM regulators ;)

Hi!, thank you for yours videos, I am learning a lot, I just discover you today. Can I ask something?.. I need to power an ESP8266 from 12V, all the time this 12V are OFF, when 12V comes up, ESP goes up, work for 5minutes and goes to sleep until 12V goes down, because 12V work only 5 minutes. In this case, Can I use a LD1117v33? with head sink...I am stack with this, if you can answer me.... I really thank you.

I commented about the same conceptual error but in a direct non-ironical way

+aiden1015 yep, that will be in p2 - good point about SMPS efficiency - thanks for adding that

you mean regulators with an adjust pin? or using two resistors as voltage regulators?

+Kevin Darrah two resistors as a voltage divider

I don't think using two resistors and making a voltage divider works good as a power supply. People use this trick to step down the voltage, but the load in the parallel to the second resistor, or the resistor that generates the desired voltages across it, has a very very large load across it and the currents are flowing at the signal levels and hence it works. When it comes to an actual device or a load, which demands current, the actual equivalent resistance isn't the same. The configurations change entirely! The voltage fluctuates and that depends upon the load. Voltage divider works as long as there is no change in the network configuration, but as long as you connect a load, configuration isn't the same anymore. That's why engineers have build "Voltage regulators" which, despite any change in the load demand, keep the voltage at the output constant by the closed loop feedback. But you can still use Zener diode based voltage regulator if you don't want to run into the complex and fancy stuff like DC-DC boost converter. It is simple and fairly keeps the voltage across it constant.

Yes, 50% of the 16x2 LCD siaplays can run on 3.3V. Typ: 2.5mA, max: 3.5mA for some models, search for datasheet!

maybe, but I think the 1262 can handle quick 500mA peaks...

Please i beg you i am stuck with this problem long time www.esp8266.com/viewtopic.php?f=6&t=12306 www.esp8266.com/viewtopic.php?f=6&t=11390

that is very strange - that last video I made with the radar gun had some serious peak currents - average of over 250mA and I used the 1262 for that project with no problem. Eh, try throwing down 100uF caps across the in and out caps.

I will give it a try but I see on this video that you used also 5V from the serial adapter+batteries . did u try'd the regulator with batteries only with esp8266 ?

nope haven't tried running with batteries

+OtakuSanel Could you please explain little bit what other options do you mean. If you have links to video or blog post please share )

+OtakuSanel Buck Convertor?

+Ivan Romanenko switch mode regulators(Buck to lower and Boost to increase voltage). once you get past the most basic of electronics they are used absolutely everywhere and real low power application use them exclusively since they can be over 90% efficient. linear regulators are horrendously inefficient and just waste tons of power.

+Big Jay yup. if he wants to do anything low power he should be comparing various buck converters. any buck will beat any linear but then there are various buck converters depending on your needs with varying efficiency so comparing them would make sense. comparing linear regs for low power applications makes absolutely no sense.

+OtakuSanel Yea, this is just part1 to this series. I'll get into Buck switch mode regulators, but even with them you'll have to watch out for quiescent current draw. I was just thinking about this and how it would be cool to see how much longer (theoretically) you could run off a battery with a switch mode converter - I could show it by the numbers and see things like if you have 50mA bursts for 100ms, what is equivalent drain when you're in standby mode?