User Manual

CHAPTER 1. Before Installation
1-12 © SAMSUNG Electronics Co., Ltd.
1.6 Static Electricity Prevention
1.6.1 Damage Prevention
When handling items sensitive to static electricity, abide by the following rules to avoid
damaging elements of circuit boards:
y Wear grounded wrist straps when handling a circuit board.
y Circuit boards should be kept away from materials that generate static electricity, such
as plastic, acrylic board, paper, and styrofoam.
y Circuit boards should be stored in antistatic boxes.
y The humidity within the equipment room should always be 40~70 %.
1.6.2 Causes of Static Electricity
Factors of man-caused static electricity and the generated voltage are as follows:
Table 1.1 Cause and Voltage of Static Electricity
Cause Average Voltage Generated(V)
Walking a linoleum floor 5, 000
PCB wrapped in styrofoam 5, 000
Removing a bubble plastic cover from a board 20, 000
Walking a carpet floor 15, 000
Ceramic DIPS wrapped in styrofoam 5, 000
1.6.3 Damage Voltage
Damage voltage of each element due to static electricity is as follows:
Table 1.2 Damage Voltage due to Static Electricity
Element Damage Voltage(V)
MOSFET 100~200
JFET 240~10, 000
CMOS 250~2, 000
TTL 250~2, 000
Bipolar TR 300~2, 500
ELC 500 or higher
SCR 680~1, 000