bleeder

The term leakage resistor is used for a high-impedance resistor connected in parallel with a capacitor, but also for a resistor against protective earth. The former is called a bleeder or bleeder resistor. It is a high impedance resistor connected in parallel with capacitors to compensate for the residual charge of the capacitor.

When a capacitor is charged and then disconnected from the voltage source, the charge on the capacitor equalizes over a longer or shorter period of time, depending on the capacitance and internal resistance of the capacitor. The bleeder resistor connected in parallel provides a defined equalization time of the potentials at the capacitor. Capacitors with bleeder resistance are identified by a resistor symbol connected in parallel with the capacitor symbol.

The term leakage resistance is also used to describe the discharge of electrical charges, for example when the floor becomes electrostatically charged and this electrostatic charge( ESC) must be discharged to earth. The aim is to protect people against electrostatic discharges( ESD) and also sensitive semiconductor components, Electrostatic Sensitive Devices (ESD), against damage and accordingly to create an Electrostatic Protected Area( EPA). Conductive floor coatings are used for this purpose.

Depending on the leakage resistance, a distinction is made between electrostatically conductive floors, Electrostatic Conductive Floor( ECF), which are floors with a leakage resistance of `lt1*10^6` Ohm, dissipative floors, Dissipative Floor( DIF), with leakage resistances between `lt1*10^6` Ohm to `lt1*10^9` Ohm and astatic floors, Anti Static Floor( ASF), which reduce the build-up of charge by foot traffic. These floors are not necessarily made of conductive material, they can also be parquet or wooden floors.

For cemented floors, the resistance to discharge depends on the moisture content and relative humidity. The values of earth leakage resistances are between `10^4` Ohm and `10^9` Ohm. Since the leakage resistance increases as cemented floors dry out, the required earth leakage resistance of `10^6` Ohm cannot be ensured.