THD3 Series - Recycling Timer

Littelfuse Recycle Time Delay Relays
The THD Series combines accurate timing circuitry with high power, solid-state switching. It can switch motors, lamps, and heaters directly without a contactor. The THD3 has equal on and off time delays. A single RT sets both time delays. You can reduce labor, component cost, and increase reliability with these small, easy-to-use THD Series timers.


Operation (Recycling Flasher - ON Time First)

Upon application of input voltage, the output energizes and the T1 ON time begins. At the end of the ON time, the output de-energizes and the T2 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 time delays, and returns the sequence to T1 ON time.


Operation (Recycling Flasher - OFF Time First)

Upon application of input voltage, the T2 OFF time begins. At the end of the OFF time, the T1 ON time begins and the load energizes. At the end of T1, T2 begins and the load de-energizes. This cycle repeats until input voltage is removed.
Reset: Removing input voltage resets the output and the sequence to T2 OFF time.

Access specifications, certifications, check availability and order parts below

Catalog #Input
Voltage (V)
Storage Temperature (F/C)Time Delay RangeSample capable
THD3C42A0120VAC-40° to 85°C (-40°F to 185°F)ON time first: 0.1 - 10s; OFF: 0.1 - 10sNo