Specialized - Cathode Ray ·CathodeRay
Round-glass P4 television picture tube using magnetic focusing and deflection, with white medium-persistence fluorescence, approximately 70-degree deflection, and typical 12 kV anode operation.
The 16SP4A is a direct-view, round glass cathode ray picture tube designed primarily for television applications. It features a unipotential cathode, magnetic focus and deflection, and an external conductive coating. The 16SP4A is identical to the 16SP4 except for the inclusion of a grey filter faceplate on the 16SP4A to improve picture contrast.
The 16SP4A is constructed with a round glass bulb and requires an external single-field ion trap magnet. The physical dimensions and mechanical features of the tube include:
The recessed small cavity cap serves as the anode terminal and is aligned with pin position #3 within a tolerance of ±10 degrees. The neck of the tube requires a specific clear space of 3 5/8 ± 5/16 inches to accommodate the external ion trap magnet.
The 16SP4A utilizes a unipotential cathode and a standard heater supply. The electrical connections, viewed from the bottom of the base, are assigned as follows:
| Pin Number | Connection |
|---|---|
| Pin 1 | Heater |
| Pin 2 | Grid No. 1 |
| Pin 10 | Grid No. 2 |
| Pin 11 | Cathode |
| Pin 12 | Heater |
| Cap | Anode |
The tube operates with a nominal heater voltage of 6.3 V and a heater current of 0.6 A. The direct interelectrode capacitances between the external conductive coating and the anode are:
Focusing and deflection are both achieved magnetically. The nominal deflection angle of the electron beam is approximately 70 degrees.
The screen of the 16SP4A utilizes Phosphor No. 4, which provides the following optical properties:
The faceplate of the 16SP4A is treated with a grey filter, which distinguishes it from the clear faceplate of the standard 16SP4.
The operating limits and typical operating conditions are specified under the Design Center system.
| Parameter | Maximum Value |
|---|---|
| DC Anode Voltage | 14,000 V |
| DC Grid No. 2 Voltage | 410 V |
| Grid No. 1 DC Negative-Bias Value | 125 V |
| Grid No. 1 DC Positive-Bias Value | 0 V |
| Grid No. 1 Positive-Peak Value | 2 V |
| Heater-Cathode Voltage (Heater negative with respect to cathode during warm-up, ≤ 15 s) | 410 V |
| Heater-Cathode Voltage (Heater negative with respect to cathode after warm-up) | 125 V |
| Heater-Cathode Voltage (Heater positive with respect to cathode) | 125 V |
Under typical operating conditions, the tube is configured with the following parameters:
The typical focusing coil current of 110 mA is specified for standard focus when the combined Grid No. 1 bias voltage and video signal voltage are adjusted to produce a highlight brightness of 20 foot-lamberts on a 10 1/4 inch by 14 1/2 inch picture size. This condition assumes the distance from the reference line to the center of the air gap on the focus coil is exactly 3.25 inches.
The 16SP4A is a 70-degree magnetic focus and deflection cathode ray tube featuring a 14 1/2-inch minimum useful screen diameter and a grey filter faceplate. Operating with a 6.3 V heater and a maximum anode rating of 14,000 V, it provides a white-emitting, medium-persistence display (Phosphor No. 4) for television receiver applications. The tube's design incorporates an external conductive coating, a unipotential cathode, and requires an external single-field ion trap magnet for proper operation.
Small-shell Duodecal 5-contact CRT base
General specifications
Properties common to every published source and operating point.
Electrical assignments shared by every tube using this base designation.
No verified pinout is recorded for this base designation.
1 physical section, each with unique specifications.
Section 1
CRT-specific anode/focus/deflection ratings retained as parameters rather than mapped to ordinary plate/screen fields.
Source-dependent data
Each block preserves the test conditions and published values from one reference. Values from different sources are intentionally kept separate.
Data set 01
Published operating points and test conditions from this source.
Maximum Anode Voltage
14000 V
Typical Anode Voltage
12000 V
Maximum Grid2 Voltage
410 V
Typical Grid2 Voltage
300 V
DeflectionAngleApproximate
70 degree
FocusingMethod
Magnetic
DeflectingMethod
Magnetic
PhosphorNumber
4
FluorescentColor
White
Persistence
Medium
Data set 02
Published operating points and test conditions from this source.
ROUND GLASS CONSTRUCTION
8 mA
Published CRT datasheet value; multiple values on a row represent the source table's separate conditions/limits.
DEFLECTION
7 degrees
Published CRT datasheet value; multiple values on a row represent the source table's separate conditions/limits.
HEATER
6.3 V
Published CRT datasheet value; multiple values on a row represent the source table's separate conditions/limits.
B FOR STANDARD FOCUS WI TM THE COMBINED GRID /1 BIAS VOLTAGE AND VI OEO SIGNAL VOLTAGE AO JUSTEO
1 V
Published CRT datasheet value; multiple values on a row represent the source table's separate conditions/limits.
MAXIMUM
14000 V
Published CRT datasheet value; multiple values on a row represent the source table's separate conditions/limits.
MAXIMUM GRID 81 CIRCUIT RESISTANCE — value 1
81 mA
Published CRT datasheet value; multiple values on a row represent the source table's separate conditions/limits.
MAXIMUM GRID 81 CIRCUIT RESISTANCE — value 2
1.5 mA
Published CRT datasheet value; multiple values on a row represent the source table's separate conditions/limits.