Frequently Asked Questions (FAQ) for Test Accessories

1) Are your DC blocks Inner or Outer or Inner/Outer?

All of the models listed in the catalog are Inner only. For Outer or Inner/Outer, please contact JFW at sales@jfwindustries.com.

2) What is the difference between an Impedance Matching Pad and an Impedance Matching Transformer?

Impedance matching pads use a resistive design to achieve the impedance change. Impedance matching transformers use a reactive design (often with a wire-wound toroid) to achieve the impedance change.

3) What are the pros and cons of impedance matching transformer versus impedance matching pads?

Matching Transformer Pros

  • Low insertion loss

Matching Transformer Cons

  • Narrow frequency band
  • Low power

Matching Pad Pros

  • Wide frequency band (and works at DC)
  • High power capabilities

Matching Pad Cons

  • High insertion loss

4) What are feedthru terminations?

A 50 Ohm feedthru termination is used to connect 50 Ohm RF cable to the high impedance inputs of test instruments (oscilloscope) and maintain proper impedance loading of the RF cable.