# Turn 9V Battery to 5V Battery (simplest and Cheapest Way)

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I want to introduce one of the minimalist way for stepping-down of 9V battery to 5V. We only need two component:

• 1x 9V battery clip (~\$0.4)
• 1x AMS1117 1A or LM1117 5V 1A output voltage regulator (~\$0.1)

AMS1117 voltage regulators are available in five fixed voltages; 1.8V, 2.5V, 2.85V, 3.3V, and 5V. Besides, it offers adjustable/fixed output and with on-chip current limiting and thermal shutdown. Common usage adds a few capacitors to both input and output where the transient response and stability is critical. But assuming to use this way for already protected device (like development boards etc.), in this work we don't need these capacitors.

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## Step 1:

Cut the plastic cover of the 9V battery clip and remove the cables from it by heating the solders. Then, place the AMS1117 near to positive head of the clip, as seen in picture. You should widen the distance between legs of AMS1117. Finally solder the legs and wires as seen in the picture.

Enjoy!

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## 7 Discussions

No.

(Well, maybe just in an emergency, for some short calls.)

Take a phone battery - a common one like the iPhone 5s has a capacity of 1560mAh.

Even a (very expensive - like 10US\$ apiece) lithium 9V battery has only 1000mAh (the fact that it has 9V instead of just 5V doesn't matter, those 4 volts get converted to heat by the regukator...) an alkaline battery is more like 500mAh and a zinc-carbon like 250 mAh...

And don't forget that the regulator has no heat sink at all. Remember those 4V voltage difference? Multiply the current needed (and a charging smart phone may want like 2A) with thos 4V to get the power this teeny tiny regulator has to convert to heat. Any more than 200mW (or 50mA) - I'm just guessing here as the data sheet says nothing about the IC in mid air - will probably fry the chip.

This circuit may be okay for small loads - a few 10s mA - but keep in mids that the data sheet states a minimal load of 10mA for a stable regulation...

Thank you very much for your guidance. I haven't faced any heat problem for low current circuit such feeding a few led circuit for a short period of time. It is not convenient for continuous usage due to the power waste.

You still did a really cool project! I like the execution!

Very correct! Well said. That series type voltage regulator is a power waster.

Absolutely right! First, I had assembled this to a clock circuit for battery supply/backup but the battery stand only for a week even there was (theoretically) zero current.

Nice idea, I'm going to make this. I will have to wait until next time I order some more parts so I don't pay a too much for shipping.