But when I measure the voltage between the two outputs O I note 10v, it's right?
do I need to use the output of LM78L05 and the gnd of LM79L05.
First off you need capacitors from input to ground on both regulators.
Please, can you explain why i need capacitors to input?
How i can lower voltage to 3v3?
Please, can you explain why i need capacitors to input
1.0mF will be ok?
but i need to power an 23k256 too, that work with 3v3. How i can lower voltage to 3v3?
That part is an SPI device so you will have to lower the drive voltage from the arduino. What I have used for this is a 74LS07 open collector buffer. You get 6 in on IC package, the inputs come from the arduino and the outputs to the SRAM with a 1K8 or so pull up resistor to the SRAM's 3V3 supply. The output of this chip can be fed straight into the arduino.
why you are suggesting using a 74LS07 instead of the simpler option of a voltage divider?
Quotewhy you are suggesting using a 74LS07 instead of the simpler option of a voltage divider?Voltage dividers can often slow down the rise time of the edge given the capacitance of the input. On the Ada wave shield their version 1 had voltage dividers but they changed to level translators for version 2 because of the trouble the users were getting with dividers. With a buffer ( which I already had so that was a plus factor for that part ) the falling edge could be very fast and the rising edge controllable by the size of the pull up resistor.
So I don't see that using the 'LS07 improves the rise time.
You don't need the -5V supply at all. The INA122 will work down to 2.2V total supply voltage and its common mode input voltage includes ground. So ditch the 79L05 and connect pin 4 of the INA122 to ground instead. See Fig 5 on the datasheet.
Voltage dividers can often slow down the rise time of the edge given the capacitance of the input. On the Ada wave shield their version 1 had voltage dividers but they changed to level translators for version 2
QuotePlease, can you explain why i need capacitors to inputTo lower the impedance of the voltage source to prevent oscillation of the regulator.Quote1.0mF will be ok?For those parts you linked to then yes. But only if the part is actually made by the same manufacturer who wrote the data sheet.
QuoteHow i can lower voltage to 3v3?First off, many but not all standard-size Arduino boards have a 3.3V v.reg on board. You can add your own on other boards, but the zener idea may work. Secondly, if you have an Arduino board that runs at 3.3V rather than 5V, you canprobably power it off a 5V regulator ok. However, you'll be running a bit close on loading with powering from a 78L05, which can deliver only 100-mA. Would be better to use a 7805 v.reg, ie 1 Amp device.Thirdly, if you have mixed systems of 5V and 3.3V, you will need level-shifters to interfacethe 23K256 to 5V I/O pins on an Arduino.[Edit: I meant to say you can probably supply 5V to the Vin pin of a 3.3V board to powerthe 3.3V v.reg on the board].
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