AUTOMATIC CURRENT MEASURING DEVICE FOR THREE ELECTRODE TUBE OF COLOR PICTURE TUBE

摘要

The circuit for measuring the cathode current automatically to test the CRT characteristics applies the voltage of a first power supply (60) to a first grid (2) after turning an automatic switch (SW) to a contact (a). Then the regulated voltage of a second power supply (70) is applied to second and third grids (3,4) until the current flowing to the cathode maintains about 0.5 mA. After setting the voltage of the second power supply, the switch turns the contact from a to b to pass the current to a resistor (RI). The voltage applied to the resister is converted to the digital data and provided to a host computer (40) through an interface (30) . The computer compares this data to the reference one and displays the results to the operator.