CYG401 High-Frequency Dynamic Pressure Sensor: 4 to 100 MPa Series

Piezoresistive sensors use a strain-gauge bridge implanted in a silicon diaphragm; they give a true DC output and respond to both static and dynamic pressure. Piezoelectric sensors use a crystal that generates charge on dynamic events but discharges over time, so they lose DC reference. For detonation and shock-wave work both Chinese and US military standards recommend piezoresistive as the first choice because the static reference is preserved through the entire transient and post-event window. The CYG401 dual-bridge compensation passes over a flush diaphragm, so what you measure is the incident wavefront, not a structure-modified version of it.

The cavity-less flush diaphragm sits directly at the wetted face with no recess, channel, or volume in front. Any cavity between the wave and the diaphragm acts as a Helmholtz resonator and adds ringing to the rising edge that destroys dynamic fidelity. CYG401 uses a stainless-steel diaphragm flush with the housing face. The flush mount keeps the wavefront in direct contact with the silicon strain bridge with no acoustic volume in between, so the rising edge of the transient is preserved without resonance distortion.

Estimate the peak amplitude of your event, then pick the range whose full-scale value sits 30 to 50 percent above that peak. That gives headroom against shot-to-shot variability without sacrificing bridge sensitivity. If the peak straddles two ranges across your test matrix, it is usually better to oversize slightly than to clip.

For confined-chamber detonation work or any test where IR flash from the event can reach the sensor face, specify the anti-IR optical filter option. The optical interference would otherwise couple into the silicon bridge and produce a transient false signal that overlays the real pressure waveform. For dry hydraulic work or the sensor is within direct line-of-sight of an open flame or explosive flash, specify the F4 anti-IR option — the chip-level optical coating blocks the IR pulse before it can saturate the silicon junction and clip the rising edge.

Mount on a rigid fixture clamped at the M20×1.5 thread; never clamp on the sensor body. Position the cavity-less flush diaphragm directly at the wetted face of the pressure chamber or pipe wall. Use the double-shielded twisted anti-interference cable when running near sources of EMI. Keep the cable out of the line-of-sight and out of the wave path so cable whip does not show up as electrical noise on the rising edge.

For sustained operating temperatures above 85°C, or transient temperatures above 125°C, step up to CYG402 high-temperature variant. For sub-MPa events such as gas-deflagration vessel testing or liquid-medium shock-tube work below 1 MPa, use CYG405 low-pressure variant. All three share the cavity-less flush diaphragm, dual-bridge sensing element, and M20×1.5 mount thread, so a single mount fixture works across the dynamic set.