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Littelfuse KRDR Series

10 variants · Littelfuse

About the Littelfuse KRDR Series

The Littelfuse KRDR Series series groups 10 related part numbers, each listed with full specifications, a datasheet where available, and an RFQ option. The listed variants share a common mounting of Chassis Mount, package of Bulk and timing initiate method of Input Voltage. Variants differ by delay time, supply voltage and timing adjustment method, so you can match the exact delay time your application requires using the selection guide below.

Select a variant by

Delay time
0.1 Sec to 10 Sec · 1 Min to 100 Min · 1 Sec to 100 Sec · Fixed, 25 Min
Supply voltage
12 VDC · 24 VDC · 120 VAC
Timing adjustment method
Fixed · Screwdriver Slot

Shared specifications

Mounting
Chassis Mount
Package
Bulk
Timing initiate method
Input Voltage
Type
Mechanical Relay

Variant comparison

ParameterKRDR320B0KRDR420A3KRDR120A0KRDR121A1KRDR321A4KRDR321B4
Delay time0.1 Sec to 10 Sec0.1 Sec to 10 Sec0.1 Sec to 10 Sec1 Sec to 100 Sec1 Sec to 100 Sec1 Min to 100 Min
Supply voltage24 VDC120 VAC12 VDC12 VDC24 VDC24 VDC
Timing adjustment methodScrewdriver SlotScrewdriver SlotScrewdriver SlotScrewdriver SlotScrewdriver SlotScrewdriver Slot

Request a quote on any Littelfuse KRDR Series part number and we confirm price, availability and lead time per line — including end-of-life and allocation-constrained variants.

All variants