Explained below are the main meanings used for base connection diagrams of CRT and notes when using such symbols.

Cathode (K)
The source for electron emission.  In the case of instrument tubes, since high-frequency signals are input to the deflection system.  G2 electrode and deflection system are actuated at near the grounding porential.  Therefore, negative voltage of the specified acceleration voltage should be applied to the cathode.

Grid No. 1 (G1)
This is used as an electrode for controlling electron current.

Grid No. 2 (G2)
This is an acceleration electrode.

Anode No. 1 (P1)
This is focus electrode for adjustment of spot size.



Anode No. 2 (P2)
This is electrode for adjustment of astigmatism.  This electrode is located at the cathode side of the Y deflection plates of an instrument Tube.  Astigmatism component can be corrected by adjusting the voltage of this electrode.



Anode No. 3 (P3)
The post acceleration system refers to a system in which the acceleration voltage is raised after electron beam passes the deflection system so that the output brightness can be increased without a sacrifice of the deflection sensitivity of an instrument tube.  P3 shows the final acceleration electrode of this system.

X Deflection Electrode and Y Deflection Electrode (X, Y)
An electrostatic deflection plates located on screen side is called "X deflection electrode" and the electron gun side is "Y deflection electrode".  The both electrodes should be operated by push-pull operation.  If an asymmetric voltage is applied, the geometry and focus balance will worsen, resulting in incomplete exhibition of the performance.
Design the mean potential of the deflection plate (Edx, Edy) for both X and Y as near as possible at the potential of G2 and P2, and minimize the potential difference between A and Y.
If the difference between the mean voltages of the deflection plates of X and Y (Edx-Edy) is too large, exhibition of the sufficient performance may be prevented by the worsened focusing and geometry.

Isolation Shield (ISD)
This electorde is located between the deflection electrodes of X and Y.  In some types of tubes, this is internally connected to other electrodes.  Unless otherwise specified, set this electrode so that the voltage to be applied will be between the mean voltages of the deflection electrodes [(Edx + Edy) / 2].  Note that this voltage affects deflection sensitivity, geometry, focus, and linearity, In some types of tubes, Geometry is corrected by adjusting this voltage.

Post deflection acceleration shield (PDS)
This shows a mesh electrode for shielding the deflection system of an instrument tube from the post acceleration electric field.