Arduino Forum

Using Arduino => Installation & Troubleshooting => Topic started by: yaantey on Jan 07, 2012, 06:16 pm

Title: What is arduino Uno's ADC input Current Min and Max?
Post by: yaantey on Jan 07, 2012, 06:16 pm
What is arduino Uno's ADC input Current Min and Max? Is the input min 40mA?
Title: Re: What is arduino Uno's ADC input Current Min and Max?
Post by: Onions on Jan 07, 2012, 06:36 pm
The inputs all have a very high resistance, so it will only draw a very small current. In order to draw more current, it must be at a higher voltage. Anything above 5V and it will be damaged.

Onions.
Title: Re: What is arduino Uno's ADC input Current Min and Max?
Post by: smeezekitty on Jan 07, 2012, 09:33 pm
They are high impedance input and will draw only uA.
Title: Re: What is arduino Uno's ADC input Current Min and Max?
Post by: kf2qd on Jan 08, 2012, 02:43 am
The ADC inputs are voltage sensing, and not current sensing. They are high impedance and will put little load on a circuit. The do not sink, they just sense. They do not draw any current, they sense voltage.

They have a MAX of 5V DC. If you need to sense a higher voltage you will need to make a voltage divider using a couple resistors in series.
Title: Re: What is arduino Uno's ADC input Current Min and Max?
Post by: cmiyc on Jan 08, 2012, 03:16 am

What is arduino Uno's ADC input Current Min and Max? Is the input min 40mA?


Min is about 0V and max is about whatever VCC is set to.

Analog in and probably tolerate 40mA.  However, since AnalogIn is a voltage measurement, the question of why such high current needs to be asked.
Title: Re: What is arduino Uno's ADC input Current Min and Max?
Post by: smeezekitty on Jan 08, 2012, 04:24 am
Also the analog pins can source/sink current if set as output in software.
Code: [Select]

pinMode(A1, OUTPUT);

In such case, their current capacity is the same as the other digital pins, 40ma absolute max <30ma recommended.

Title: Re: What is arduino Uno's ADC input Current Min and Max?
Post by: Grumpy_Mike on Jan 09, 2012, 08:19 pm
Quote
What is arduino Uno's ADC input Current Min and Max?

The minimum current is 0uA the maximum is 1uA as specified in the data sheet Section 28 under input leakage current.