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POWER DISSIPATION CONSIDERATIONS
The A4988 driver IC has a maximum current rating of 2 A per coil, but the actual current
you can deliver depends on how well you can keep the IC cool. The carrier's printed
circuit board is designed to draw heat out of the IC, but to supply more than
approximately 1 A per coil, a heat sink or other cooling method is required.
This product can get hot enough to burn you long before the chip overheats. Take care
when handling this product and other components connected to it.
Please note that measuring the current draw at the power supply will generally not
provide an accurate measure of the coil current. Since the input voltage to the driver
can be significantly higher than the coil voltage, the measured current on the power
supply can be quite a bit lower than the coil current (the driver and coil basically act
like a switching step-down power supply). Also, if the supply voltage is very high
compared to what the motor needs to achieve the set current, the duty cycle will be
very low, which also leads to significant differences between average and RMS currents.
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