Description : measures the voltage at Gnd and the middle of the potentiometer . Do not connect the motor when measuring the voltage , otherwise it is easy to burn the drive . When measuring the voltage , you should connect the power , and do not just connect the USB power supply . Pay special attention to the direction , do not insert it backwards ! Package Includes : 5 Pieces TMC2208 V1 . 0 5 Piece Heat sink 1 Piece Screwdriver 5 Pieces In - line texture eraser Note : Instructions for use : 1 . When using on the printer control board , please keep 3 jumper caps under the socket 2 . Because of the characteristics of the chip , be sure to do a good job of heat dissipation ! The heat sink is directly attached to the PCB , pay attention to the direction of the heat sink , otherwise it will cause the heat sink and the pins to be connected together and cause a short circuit . Refer to the following figure for how to use it . 3 . The direction of the motor is exactly the opposite of that of the A4988 and DRV8825 . If you want to directly replace the A4988 , please adjust the firmware or adjust the motor wiring .