Specialized - Cathode Ray ·CathodeRay
12ZP4A
Sheldon 12ZP4A 12¼-inch monochrome television CRT with magnetic focus and deflection, ion-trap gun, gray-tinted metal-backed P4 white screen and 6.3 V 0.6 A heater.
- Sections
- 1
- Base
- 12D
- Socket code
- -
- Base pins
- 12
- Nominal heater
- 6.3 V / 600 mA
General specifications
Tube and section characteristics
Properties common to every published source and operating point.
Heater and base
- Base
- 12D
- Socket code
- -
- Base pins
- 12
- Nominal heater voltage
- 6.3 V
- Nominal heater current
- 600 mA
- Parallel heater voltage
- -
- Parallel heater current
- -
- Series capable
- No
12D - Terminal pinout
Electrical assignments shared by every tube using this base designation.
No verified pinout is recorded for this base designation.
Section ratings
1 physical section, each with unique specifications.
Section 1
Cathode Ray
- Max plate voltage
- 12000 V
- Max screen voltage
- 410 V
Sheldon 12ZP4A CRT. Maximum anode 12000 V DC, grid2 accelerator 410 V DC, grid1 negative bias -125 V, positive DC bias 0 V, positive peak +2 V; heater-cathode ±140 V normal, heater-negative 410 V warm-up <=15 s. Typical anode 11000 V, grid2 250 V, grid1 visual cutoff -27 to -63 V; focusing-coil current ~135 mA, ion-trap current ~85 mA. Grid1 circuit resistance max 1.5 MΩ. P4 white medium persistence gray-tinted (~70% light transmission) metal-backed screen; magnetic focus and deflection ~54°. Cathode capacitance 5 pF, grid1 capacitance 8 pF, external coating-to-anode2 500–2500 pF. Separate anode bulb cap J1-21.
Source-dependent data
Operating conditions by source
Each block preserves the test conditions and published values from one reference. Values from different sources are intentionally kept separate.