oPossum wrote:This is the circuit I built for testing the behavior of various iProducts. It uses ordinary 5% resistance values and has a jumper block for setting the max current draw.
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1% resistors could also be used...
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A couple questions please. In your evaluation network (47k, 47k, 18k, 47k) my calculations say the tap voltages will be 1.53v and 2.13v. Normally the voltages are shown to be 2.0v and 2.7v (43k, 31k, 49k). Is there a difference in the way an iDevice will react to the different voltages? Must the 1.53 & 2.13 voltages be used to get the 2A charge rate for the iPad? From your two videos it looks like you use the 47k, 47k, 18k, 47k network for all 3 tests. Does the iPad 3 behave differently than the iPad 2? When you set the evaluation network for 0.5A charge, the iPad showed it was drawing about that amount. Is that indicating that the iPad is running off the charger but not charging the battery?
Thanks for your help,