PTHF Series - Percentage Timers

Littelfuse Percentage timers
The PTHF Series can be used for a variety of applications from chemical metering, to temperature regulating, to energy management. The infinite adjustability from 1 to 99% provides accurate percentage on control over a wide factory fixed cycle period. When mounted on a metal surface, it can be used to drive solenoids, contactors, relays, or lamps, up to 20A steady, 200A inrush. PTHF is the suggested replacement for the PT Series.

Operation (Percentage)

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. Increasing the ON time decreases the OFF time. The total cycle period is equal to the ON time plus the OFF time. The total cycle period is factory fixed. ON time range is 1 to 99 percent of cycle period.

Removing input voltage resets the output and time delays, and returns the sequence to the T1 ON time.

Access specifications, certifications, check availability and order parts below

Catalog #Input
Voltage (V)
Storage Temperature (F/C)Time Delay RangeSample capable
PTHF4900DK120VAC-40° to 85°C (-40°F to 185°F)Adjustable from 1-99% / RT≅100kΩNo