Probe Fixture Style
With Terminal Probe Fixture Style
Wire probes, which are elastic throughout their length, are generally referred to as "needle probes".
The structure of these probes are in fact very simple, wherein a special, highly elastic wire is used to bring about spring characteristics in the probe itself.
Pin pressure is generated by utilizing elastic deformation and restoring force of the wire itself when pressure is applied to the probe.
Basic testing jigs consist of a plate for fixing this wire probe and a guide plate for positioning on each chip.
Pin pressure is determined based on the material (hardness), wire diameter, and the distance between the fixing plate and the guide plate.
Moreover, the spring characteristics of wire probes differ from those of coil-spring probes in that they increase rapidly up to a certain stroke value and stay stable at higher stroke values.
However, the pin pressure decreases at stroke values that exceed the "limit of elasticity" of the probe. Wire probes may not be restored at such values, where use of them must be avoided.