Capacitor for illuminated switch KS1 KS-1

What is this capacitor for?

The KS-1 capacitor is installed in parallel with a switch featuring backlighting to prevent flickering or faint glowing of energy-saving fluorescent lamps and LED bulbs. Without it, the small current flowing through the switch’s backlight may be sufficient to cause LEDs or electrodes in LED/CCFL lamps to emit a weak glow—even when the switch is turned off. This component eliminates this effect without requiring replacement of the switch with a non-backlit model.

How does it work and where is it installed?

Using a single capacitor with a capacitance of 0.1 µF and a rated voltage of 250 V AC, it balances the voltage across the lamp terminals when the switch is in the “off” position. Installation is simple: it is connected directly behind the switch, between the live and neutral wires, typically inside the distribution box or behind the switch housing. No special tools or modifications to the installation are required. It works effectively in circuits with either a single or multiple lighting points controlled by the same switch.

Why use it?

• Prevents flickering — lamps do not glow after being turned off, even in the presence of the smallest “leakage” currents from the backlight.
• Does not affect brightness — does not reduce light output when the lamp is turned on, nor limits LED performance.
• Compatible with dimmers — can also be used in LED dimmer circuits, where similar issues may occur.
• Simple construction — made from insulating material, without plug-in terminals — durable and resistant to environmental conditions.
• Maintenance-free — requires no inspection or servicing after installation.

This is not a protective or filtering component—it is a purely functional element designed to solve a specific problem: the improper behavior of modern light sources when controlled by switches with backlight LEDs.