PTR uses steel as the standard material for the plungers. The stability of this material is good in comparison with others, and is extremely suitable for aggressive probe tips such as the “pointed tip” or the “chisel”. The electrical properties are improved by the preferred gold coating.

Copper Beryllium  
Copper beryllium is superior to steel in respect of the long-term stability of the electrical properties. Adding beryllium allows the materials to be easily processed, without completely losing the excellent properties of the copper.  

Brass is a relatively soft material which is good for manufacturing purposes. Because of the high copper content, the electrical properties are also good, and for this reason, the material is mainly used for receptacles and barrels. However, brass is also a very popular plunger material for battery charging contacts, which normally do not have to withstand a very high number of load cycles.

Bronze is used as a base material for receptacles and barrels; it offers good electrical properties and can be both turned and deep drawn.

Nickel Silver
Nickel silver is a very interesting material for receptacles because it is especially corrosion-proof and can be manufactured using the deep drawing process. Its copper content also makes it an acceptable conductor.

Spring Steel
High-strength spring steel is what is normally used to manufacture springs. It provides excellent properties which permit the manufacture of test probes with long operating times and balanced forces. The temperature range is from -30°C to 120°C. The springs are coated with gold or silver.

Stainless Steel
Stainless steel is used for springs in situations which require greater temperature stability than those which require standard springs. Temperatures from -40°C to 250°C (max. period of one hour) are possible. Good corrosion resistance is an additional advantage of stainless steel.

High-quality plastics which can resist high temperatures are used to isolate the probe tip of switching test probes or as an isolator in the test probe itself. This material is also used as a carrier material for interface pin blocks. This is where PTR can benefit from its extensive experience of the terminal block sector.