The P170CF uses a 5718 triode. It requires a 170 Ω termination which is built into the 517 and needs to be externally connected for other instruments (the B170-R terminator with UHF connectors was available for this).
|Input impedance||With attenuators: 12 MΩ // 5 pF @ min att. − 1.2 pF @ max. att.|
- The P170CF is discussed in the Tektronix Type 128 manual (PDF)