Specialized - Cathode Ray ·CathodeRay
Cathode-ray display tube with approximately 65-degree deflection, typically operated from a 12 kV anode supply with a 250 V second-grid supply and adjustable focus voltage.
The 17BCP1 is a cathode ray tube designed for display applications requiring high ambient light performance. It features electromagnetic deflection with an approximate 65° deflection angle and electrostatic focusing. The tube incorporates a metal-backed screen and a zero-focus-type electron gun, which provides substantially automatic focus independent of variations in the accelerator voltage. The 17BCP1 does not require an ion trap. The designation represents the 17BC tube type equipped with a P1 phosphor screen, though the tube is also available with P2, P7, P11, P15, and P19 phosphors.
The 17BCP1 is constructed with a rectangular glass envelope and a metal-backed screen. The metal backing is designed to handle high ambient light levels and provides protection against ion burns, eliminating the need for an external ion trap magnet.
The physical dimensions of the tube are as follows:
The electrical connection to the anode is made via a small recessed cavity cap located in the bulb wall, which connects to the conductive inner wall coating and Grid #3.
The 17BCP1 utilizes an indirectly heated cathode. The heater is rated for a nominal voltage of 6.3 Volts and a current of 0.6 Amperes.
The tube uses a Small Shell Duodecal 7 Pin base, designated as RTMA 12L. The pin connections, viewed from the bottom of the base, are configured as follows:
| Pin Number | Connection |
|---|---|
| Pin 1 | Heater (H) |
| Pin 2 | Grid #1 (G#1 / control electrode) |
| Pin 6 | Focus |
| Pin 7 | No Connection (NC) |
| Pin 10 | Grid #2 (G#2 / accelerating electrode) |
| Pin 11 | Cathode (K) |
| Pin 12 | Heater (H) |
| Recessed Cap | Anode (Conductive inner wall coating and Grid #3) |
The 17BCP1 operates with electrostatic focusing and electromagnetic deflection. The zero-focus-type electron gun is designed to maintain focus automatically, even when the accelerator voltage varies.
Under typical operating conditions, the tube is set up with the following parameters:
To ensure reliable operation and prevent damage, the following maximum ratings must not be exceeded:
The external circuitry connected to the electrodes must comply with specific resistance limits to maintain stable operation:
The 17BCP1 is a 65° electromagnetic deflection cathode ray tube featuring electrostatic self-focusing and a metal-backed screen. Operating typically at an anode voltage of 12,000 V and a Grid #2 voltage of 250 V, it provides a bright display suitable for high ambient light environments without requiring an ion trap. The tube is built on an RTMA 12L Small Shell Duodecal 7-pin base and is available with several phosphor options, including the standard green P1 phosphor.
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
Published applicable promoted ratings populated; remaining device-specific values retained as parameters.
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.
Typical Anode Voltage
12000 V
Typical Grid 2 Voltage
250 V
Grid 1 Voltage Range
-63 to -27 V
Focus Voltage Range
-500 to 500 V
Grid 1 Circuit Resistance Maximum
1.5 Mohm
Grid 2 Circuit Resistance Minimum
470 ohm
Anode Circuit Resistance Minimum
15000 ohm
Deflection Angle
65 degree