Micro-Measurements Full-Bridge Sensors Based on Advanced Sensors Technology

Micro-Measurements announced that it has expanded its product line of Transducer Class full-bridge strain gages based on Advanced Sensors technology. Offering several advantages over bonding multiple, individual strain gages, the devices are now available with smaller, higher resistance patterns to serve a variety of bending and torque/shear applications.

The strain gage has been in use for many years and is the fundamental sensing element found in many types of precision force measuring transducers, including pressure, torque, load, and position. The Wheatstone bridge electrical circuit is most commonly used to sense strain gage resistance changes. This circuit requires four electrical resistance elements connected into a series/parallel configuration. One, two, or four strain gages can serve as the four resistance elements, with precision resistors making up the partial configurations. The full-bridge circuit (with four active strain gages) provides for the highest measurement sensitivity and the best extraneous temperature cancellation.

Built using Micro-Measurements’ Advanced Sensors strain gage technology, the S5056, S5020, S5046, and S5047 strain gages offer improved grid-resistance tolerance and grid-to-grid temperature matching compared to traditional gages. Micro-Measurements offers a wide range of pattern configurations and resistance ranging from 350 Ω to 20 kΩ. The addition of gold-plated solder pads improves lead wire attachment and solder-joint reliability, reducing the chances of solder pad oxidation prior to attaching the lead wires.

Compared to bonding multiple individual strain gages, the full-bridge devices provide simplified, more precise alignment and reduced bonding operations. All four active arms of the Wheatstone bridge circuit are formed on a single carrier, allowing the entire bridge to be bonded at one time. All intrabridge connections are integrated into the pattern, thus eliminating intrabridge soldering.
“Eliminating intrabridge wiring and soldering helps to reduce zero TC problems,” said Ron Zukerman, Micro-Measurements Advanced Sensors manager of marketing and sales. “With no internal bridge wiring required, soldering is reduced to just four instrument wire connections, which greatly improves reliability. In addition, with all four arms of the Wheatstone bridge being manufactured simultaneously from a single piece of foil, grid-to-grid thermal characteristics are more closely matched, and thermal output is cancelled in the bridge circuit.”

Micro-Measurements sensors are available in a variety of sizes, configurations, and mounting technologies. For the S5056, S5020, S5046, and S5047, the Advanced Sensors production line enables prototyping, one-piece, and high-volume manufacturing capabilities.

Samples and production quantities of the full-bridge sensors are available now, with lead times of six weeks for prototype samples and 12 weeks for standard orders.