Diagnostic Adapters - Capacitor

Hello,

I'm currently in the process of building a diagnostic adapter, version 2.0. However, I don't understand the purpose of component C2. It seems insignificant and is located parallel to the larger capacitor C1. Have I overlooked something?

Christian.

Hello Christian,

EL capacitors exhibit increasingly higher ohmic and then inductive impedance at higher frequencies. This means that at frequencies of several hundred MHz, the EL capacitor no longer behaves as a pure capacitor. Its ability to absorb short current surges is insufficient, which is why a smaller, non-electrolytic capacitor is often connected in parallel, such as a metallized polypropylene film capacitor (MKT, where "T" denotes the type of dielectric material).
The large ELKO capacitor handles large, longer-duration power surges, while the smaller capacitor handles surges in the higher frequency range.

Best regards, Rainer.

Thank you.

I won't leave it out, then!

Christian.