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sim900a related queries

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sumit garg

Junior Member level 1
Jul 26, 2022
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I have two queries ralated to sim 900a
1. I have a jio 4g sim which is not getting signal in sim 900a but if i will use VI sim it is getting network, but i want to use jio sim, is it possible anyways?
2.I want to use single battery to power arduino and sim900a how can i do it?


2) it's all about voltage and current. But I see no info obout these in your post.
--> please findo out of each device the
* recommended power supply voltage range
* max supply current
Tell us these values.

1.For Arduino Uno 7v-12v voltage range and datasheet states that the current limitation is 200mA.
2.For Sim 900a (GSM Module)-3.5-4.5 V voltage range and current range(2-2.5A)


Then I recommend:

A step down (buck) regulator for 7..12V input to 3.5...4.5V output and max 2.5A. No need to be isolated.
It should have a worst case input current of 1.8A (7V_in, 4.5V_out, 2.5A, 90% eff)

Thus you could use a 7..12V, 2A rated common power supply.

To keep heating in the Arduino low, choose low input voltage --> maybe 7.5V (to have some headroom)
The same for the modem: 3.7 ... 4.0V.

To keep GND bounce low:
Wire the supply to the step down. And use the GND of the step down as star point.
Add a bulk capacitor as well as a fast ceramics capacitor at the star point.

hello, thank you
this is very helpful for me
I have a small doubt like if i already have a3.7V battery ,as like you mentioned can i use step up regulators/



I´m not very familiar with Arduino hardware.
You say it´s supply voltage is 7..12V....I have to believe it.
On the other hand... Doesn´t an Arduino Uno run from USB? Which is in the range of 4.5...5V.

If I´m not mistaken, there is an AVR on an Arduino Uno ... All AVRs I know run with something between 2.7V ... 5V.
Don´t know what else is on an Uno board and what power supply requirements they have.


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