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ocrdu
ocrdu
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I'm trying to connect an ACS712ACS712 current metersensor to an ESP32 ADC pingpin. The ESP32 expectedexpects 3.3V3 V, but the ACS712 can reach 4.5V5 V.

When there's no current going thruthrough the ACS712, its signal is 2.5V5 V, so I made a test: I setmade a voltage divider using 330Ω330 Ω / 1kΩ1 kΩ resistors and the instead of the 2.5V5 V dropping to 1.88V88 V as expected, it dropped to something like 0.4V4 V.

As soon as I connect the 1kΩ1 kΩ between signal and ground, the signal drops from 2.5V5 V to 0.4V4 V.

Using much bigger resistors (4.7kΩ7 kΩ / 10kΩ10 kΩ) it works as expected, but I'm left wondering why it doesn't with smaller resistors.

Thanks

I'm trying to connect an ACS712 current meter to ESP32 ADC ping. ESP32 expected 3.3V, but ACS712 can reach 4.5V.

When there's no current going thru ACS712, its signal is 2.5V, so I made a test: I set a voltage divider using 330Ω / 1kΩ resistors and the instead of the 2.5V dropping to 1.88V as expected, it dropped to something like 0.4V.

As soon as I connect the 1kΩ between signal and ground, the signal drops from 2.5V to 0.4V.

Using much bigger resistors (4.7kΩ / 10kΩ) it works as expected, but I'm left wondering why it doesn't with smaller resistors.

Thanks

I'm trying to connect an ACS712 current sensor to an ESP32 ADC pin. The ESP32 expects 3.3 V, but the ACS712 can reach 4.5 V.

When there's no current going through the ACS712, its signal is 2.5 V, so I made a test: I made a voltage divider using 330 Ω / 1 kΩ resistors and instead of the 2.5 V dropping to 1.88 V as expected, it dropped to something like 0.4 V.

As soon as I connect the 1 kΩ between signal and ground, the signal drops from 2.5 V to 0.4 V.

Using much bigger resistors (4.7 kΩ / 10 kΩ) it works as expected, but I'm left wondering why it doesn't with smaller resistors.

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Lem0n
Lem0n
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Voltage divider dropping voltage more than expected

I'm trying to connect an ACS712 current meter to ESP32 ADC ping. ESP32 expected 3.3V, but ACS712 can reach 4.5V.

When there's no current going thru ACS712, its signal is 2.5V, so I made a test: I set a voltage divider using 330Ω / 1kΩ resistors and the instead of the 2.5V dropping to 1.88V as expected, it dropped to something like 0.4V.

As soon as I connect the 1kΩ between signal and ground, the signal drops from 2.5V to 0.4V.

Using much bigger resistors (4.7kΩ / 10kΩ) it works as expected, but I'm left wondering why it doesn't with smaller resistors.

Thanks