What factors will cause inductive charging of the device？
Dear ESD experts,
May I ask what factors in the field will cause the device induction charging? Please answer my doubts, thank you very much!
Yang,
ESDS items can be inductively charged by charged insulators or isolated conductors. The main factors that affect how much the ESDS item is inductively charged is the voltage on the insulator or isolated conductor and the distance between the ESDS item and the insulator or isolated conductor. There are also other factors involved like the size of the insulator or isolated conductor and its angle to the ESDS item.
ANSI/ESD S20.20 has 2 methods of measurement to ensure the inductive charging from insulators or isolated conductors is kept to a safe level. It states:
"• Measure the field at the location where the ESDS item is handled. The electrostatic field shall be less than 5000 volts/meter (125 volts/inch).
or
• For any process essential insulators located less than or equal to 25 mm from an unprotected ESDS item, the voltage on the surface of the insulator shall be less than 125 volts when measured with a non-contact electrostatic voltmeter. When using an electrostatic field meter, the reading shall be less than 125 volts when measured at the meter’s stipulated measuring distance.
• For any process essential insulators located more than 25 mm, but less than 300 mm from an unprotected ESDS item, the voltage on the surface of the insulator shall be less than 2000 volts when measured with a non-contact electrostatic voltmeter. When using an electrostatic field meter, the reading shall be less than 2000 volts when measured at the meter’s stipulated measuring distance.
Dear AndyN,
Ok, got it. Thank you very much for your reply!