THC / THS Series - Single Shot Timer

Littelfuse Single Shot Relays
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The TH series is a solid-state relay and timer combined into one compact, easy-to-use control. When mounted to a metal surface, the TH Series may be used to directly control lamp or heater loads of up to 20A steady, 200A inrush. Its single shot function can perform dispensing and pulse shaping operations. The initiate switch can be a momentary or maintained type of switch. Time delays can be selected from 0.1 - 600 seconds in 4 ranges. The THC Series is used for coin vending applications where fast initiate response is required.


Operation (Single Shot)
Input voltage must be applied before and during timing. Upon momentary or maintained closure of the initiate switch (leading edge triggered), the output energizes for a measured interval of time. At the end of the delay, the output de-energizes. Opening or reclosing the initiate switch during timing has no affect on the time delay. The output will energize if the initiate switch is closed when input voltage is applied.
Reset: Reset occurs when the time delay is complete and the initiate switch opens. Loss of input voltage resets the time delay and output.

Access specifications, certifications, check availability and order parts below

Catalog #Input
Voltage (V)
Storage Temperature (F/C)Time Delay RangeSample CapableCompare
THC421C120VACNO closed during timing-40° to 85°C (-40°F to 185°F)0.1 - 3s externally adjustableNo
THS422B120VACNO closed during timing-40° to 85°C (-40°F to 185°F)0.5 - 60s externally adjustableNo
THS422C120VACNO closed during timing-40° to 85°C (-40°F to 185°F)0.5 - 60s externally adjustableNo