The S125 is a volume-ready Shape Memory Alloy wire actuator, with a MOSFET switching & protection circuitry on a Printed Circuit Board substrate. The ideal uses are latch or trigger release mechanisms for battery-powered devices.

The S125 is a short-stroke latch-release or trigger-release mechanism featuring totally silent operation and thin profile typical of our Shape Memory Alloy constant-force actuators.

The S125 is optimized for battery-powered operation at 3.7 volts, but operates from 3.0 to over 9.0 volts. Actuation speed as a function of voltage is shown below.
The S125 has an on-board MOSFET switching & protection circuit, which removes power to the SMA wire when the output stage reaches the End-of-Stroke Contact. This allows the S125 to hold the end position at full load. Holding power is typically 12-15% of actuation power, allowing the S125 to maintain long-duration HOLD while consuming minimal power.
The S125 has a 3-wire interface: Input Voltage (+V), Enable (EN), and Ground (GD). The Enable voltage range is 2.5 volts to +Vin. The actuator is energized whenever the Enable line is raised ‘high’.
The S125 weighs less than 0.17 oz. (4.75 grams) – providing a Force-to-Weight ratio of over 140:1, and the overall envelope is 3.75 x 0.5 x 0.12” (95.25 x 12.5 x 3.18mm).
The S125 has a low-force bias spring to maintain tension in the SMA wire at all times.
Contact us for STEP files of the S125 actuator in both Default and Energized states.

The S125 has a Ø0.063” hole in the output shaft to attach linkages, but we recommend contacting the load only with the leading edge of the shaft, so the actuator wire remains under tension while cooling following actuation.

Features:
0.125” stroke
1.25 pounds of force
Compact
Silent
Lightweight
Actuation time: 0.25 seconds @ 3.7 volts, 0.15 seconds @ 5.0 volts
Optimized for 3.7 volt Lithium-polymer battery operation

Typical Electrical Properties
Resistance#: 2.75 Ω
Current, I: 1.35 Amps
Actuation Power (IV): 4.98 Watts
Holding Power: 0.60 Watts
Still Air Cooling Time: 2.3 Seconds

Expected battery life for N-Amp-hr, V-volt battery (derated by 1.5x):
Current * Time: 0.368 A*S 1.0E-04 A*Hr

Battery Capacity: 0.15 Amp*Hr
Battery Life: 979 actuations