Littelfuse FS491, FS400 Series, Flashers and Tower Lighting Control, 120-240VAC

In stock
SKU: FS491
Regular price $129.29
Rated voltage

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The FS491 is a low leakage AC flasher designed to control LED, or resistive loads. This product offers a solid-state output and may be ordered with an input voltage of 24V to 240VAC, in two ranges. It offers a factory fixed flash rate of 75 FPM or may be ordered with a fixed, custom flash rate ranging from 45 to 150 FPM. The FS491 is the perfect solution for LED lamp flashing.


Upon application of input voltage, the output energizes and the ON time begins. At the end of the ON time, the output de-energizes and the OFF time begins. At the end of the OFF time, the output energizes and the cycle repeats as long as input voltage is applied.

Reset: Removing input voltage resets the output and the flash sequence.


Technical Data
Operation ON/OFF solid-state flasher (continuous duty)
Flash Rate Fixed at 75 FPM ±20%
ON/OFF Ratio ≅ 50%
Custom Flash Rate 45 - 150 FPM ±20%
Voltage 120 - 240VAC
Tolerance ± 15%
AC Line Frequency 50/60Hz
Load Type LED or resistive
Output Bridge Rectifier & FET
Maximum Load Rating 120VAC to 240VAC 0.5A steady state; 5A inrush
Max. Load Leakage Current 250µA
Voltage Drop 2V typical
Mounting Surface mount with one #8 (M4 x 0.7) screw
Dimensions Dia. 23.9 mm (0.94”);
D 38.1 mm (1.5”)
Surge IEEE C62.41 - 1991 Level A
Circuitry Encapsulated
Operating/Storage Temperature -20° to 60°C / -40° to 85°C
Weight ≅ 1.1 oz (31 g)
Humidity 95% relative, non-condensing