FAQ01906 of Push Buttons / Indicator Lamps FAQ

Set the control resistance within the range for the LED lamp characteristics.

(Set the forward current for the LED lamp to 8 mA min.)

Use the following formula to find the external resistance.

Control Resistance (Recommended Values)

Calculation Example: A3D

LED lamp color: Red

When E=24V, IF=20mA, and Ta=25°C:

Based on the VF-IF characteristics in the diagram below (red), VF when IF = 20mA will be 1.7 V.

If this value is entered into the above formula, the result is as follows:

The recommended resistance is 1.1 kΩ 1 W (2 × IF2R). A margin of approximately two times is appropriate for the resistance capacity.

Applicable models: Push Buttons A3D, A3A, etc.