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Topic: 0-5 v into 0-2.5 volts ? (Read 4 times) previous topic - next topic

AWOL

Quote
how do i find the input impedence ?

It'll be in the datasheet.
Which device are you using?
"Pete, it's a fool looks for logic in the chambers of the human heart." Ulysses Everett McGill.
Do not send technical questions via personal messaging - they will be ignored.

db2db


Which takes me right back to my original reply:

"In this case, you'd use two of the same value resistors, so you dont have to do much calculating."

A micro input sure seems like it'd be high impedance.
Two 10k resistors.  This will scale 0 to 5v to be 0 to 2.5v.

Jassper



Which takes me right back to my original reply:

"In this case, you'd use two of the same value resistors, so you dont have to do much calculating."

A micro input sure seems like it'd be high impedance.
Two 10k resistors.  This will scale 0 to 5v to be 0 to 2.5v.



What he said.

If your not "powering" something then 2 equal value resistors should do it.

db2db

I should clarify:

Two 10k resistors *wired as a voltage divider*, as mentioned earlier in this thread.

Gadget999

hi guys i tried a test today with two 22 ohm resistors

i wired up a 5v voltage regulator and measure the power out

just over 5 volts

then i added the two 22 ohm resistors and the voltage went down to 2.75 volts

not quite 2.5 volts but good enough

now i rewired the circuit

this time a pressure sensor was added and powered from the 5v regulator

the output with room pressure was 1.22 volts

then i added the two 22 ohm resistors

I expected to see approx 0.6 volts

but i saw 0.18 volts ?

the voltage was not powering anything just going to my multimeter

Is the problem caused by using low value resistors, so the resistance in the wires of the multimeter could upset the reading ?

confused ;-S

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