# Successive approximation conversion

Can someone explain me from the following table on how to get the DAC output.

## 1 Answer

The "Test Value" is the "Current value" from the previous row OR'd with the "Test bit" from the current row.

The "DAC output" is the "Test Value" converted to a range of 0 to +5V.

$$\text{DAC Output} = 5V \frac{\text{Test Value}}{256}$$

And finally, if the output of the comparator is 1 (unknown input > DAC Output), then the "Test Value" becomes the new "Current value".

• Thanks a lot!This was very helpful! – Jarvis Ferns Apr 9 '19 at 21:40
• sorry for asking late, but how to get the test value? ,does it remain same for different input voltage, if so then I'm good. – Jarvis Ferns Apr 11 '19 at 8:39
• No, it doesn't. See edit above. – Dave Tweed Apr 11 '19 at 11:12