# Parasitic inductance of relay contacts

I need to switch a bank of filters operating on bands from about 2MHz to 30MHz. The parasitic series inductance of the relay contact system will have an effect on the performance of my system. Manufacturers of small encapsulated relays, like this Omron unit, don't specify this parasitic value. Has anyone done so?

• just to get a feeling of which orders of magnitude would be relevant: What are the intended inductances / capacitances in that system? – Marcus Müller May 10 '19 at 9:28
• Certainly under 0.1$\mu$H per relay, Marcus. – Brian K1LI May 10 '19 at 11:40
• I'd expect something in the region of single-digit nH, but that's just a gut feeling based on experiences of free-hanging wire inductances and a rough guess that we can model the conductors to be ca 1mm wide and ca 50mm long – Marcus Müller May 10 '19 at 19:53
• (by the way, I'm just now realizing that I always only wondered about stray capacitance of such components, not about the inductivity. Interestingly, the cheaper RF relays' datasheets don't mention inductivity at all. Some at least mention VSWR for frequency ranges; maybe that helps?) – Marcus Müller May 11 '19 at 11:22
• @MarcusMüller Thanks for the pointer, Marcus. I need up to 1kW power handling. Strangely, the Schrack "RF" series relays from the same manufacturer have no "RF" specs. – Brian K1LI May 12 '19 at 0:10