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Rectifier - Full Wave ·Rectifier-Rectifier

1768

Philips directly heated double-anode gas-filled industrial rectifier designed particularly for battery-charging equipment. Multiampere output and low forward voltage provide efficient high-current power conversion.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 2
Base: -
Socket code: -
Base pins: -
Nominal heater: 1.9 V / 11 A

Description

1768 — Double-Anode Gas-Filled Rectifying Valve

The 1768 is a gas-filled, double-anode rectifying valve designed primarily for high-current applications such as battery chargers. Featuring an oxide-coated filament, this robust valve is capable of delivering up to 6 A per valve, making it suitable for charging configurations of up to 110 lead-acid (Pb) cells.

Filament and Heating Requirements

The 1768 utilizes an oxide-coated filament designed for direct AC heating. Due to the gas-filled nature of the valve, strict adherence to filament heating times is necessary to prevent damage to the cathode before drawing anode current.

Parameter	Value
Filament Voltage ( $V_f$ )	1.9 V
Filament Current ( $I_f$ )	11 A
Recommended Heating Time ( $t_w$ )	60 seconds
Minimum Heating Time (Urgent)	30 seconds

Under normal operating conditions, a preheating time of 60 seconds is recommended. In urgent circumstances, this preheating period may be reduced to a minimum limit of 30 seconds.

Physical Design and Mechanical Specifications

The 1768 is a physically substantial valve designed to handle significant thermal and electrical loads. It must be operated in a vertical position with the base facing down to ensure proper internal gas distribution and structural integrity during operation.

Mounting Position: Vertical, base down
Net Weight: 470 g
Shipping Weight: 2800 g
Maximum Height: 240 mm
Maximum Bulb Diameter: 76 mm (with a 71 mm lower body diameter)
Side Anode Caps Diameter: 25 mm
Width Across Anode Caps: 125 mm to 145 mm

The electrical connections are divided to isolate the high-voltage anode potentials from the filament supply. The filament connections consist of two bottom leads ( $f, f$ ), while the two anodes are connected via dedicated side caps ( $a, a'$ ).

Electrical Characteristics and Limiting Values

During conduction, the 1768 exhibits a typical low arc voltage drop, which is characteristic of gas-filled rectifiers and contributes to high electrical efficiency.

Typical Arc Voltage ( $V_{\text{arc}}$ ): 15 V

To ensure reliable operation and prevent premature valve failure, circuit designs must respect the absolute limiting values specified for the device. The transformer voltage limits are defined specifically for standard full-wave rectification (Circuit a).

Parameter	Minimum	Maximum
Transformer Voltage ( $V_{tr}$ )	130 $V_{\text{eff}}$ (RMS)	285 $V_{\text{eff}}$ (RMS)
Peak Inverse Anode Voltage ( $V_{a\text{ inv p}}$ )	—	880 V
Continuous Anode Current ( $I_a$ )	—	3 A
Peak Anode Current ( $I_{ap}$ )	—	10 A
Ambient Temperature ( $t_{\text{amb}}$ )	-55 °C	+75 °C

The wide ambient temperature range of -55 °C to +75 °C allows the 1768 to be deployed in demanding industrial environments without requiring specialized climate control, provided the maximum current and voltage limits are not exceeded.

Technical Summary

The 1768 is a specialized gas-filled, double-anode rectifying valve engineered for heavy-duty battery charging systems. Operating with a high-current 1.9 V, 11 A directly heated filament, the valve requires a minimum preheating time of 30 to 60 seconds before anode load is applied. With a typical arc voltage of 15 V, it supports a maximum peak inverse voltage of 880 V and a peak anode current of 10 A (3 A continuous). Its physical construction features a vertical mounting requirement, dual side anode caps for high-voltage isolation, and a robust design capable of operating across a broad temperature range of -55 °C to +75 °C.

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base: -
Socket code: -
Base pins: -
Nominal heater voltage: 1.9 V
Nominal heater current: 11 A
Parallel heater voltage: -
Parallel heater current: -
Series capable: No

Terminal pinout

Electrical assignments shared by every tube using this base designation.

No verified pinout is recorded for this base designation.

Section ratings

2 physical sections, each with unique specifications.

Section 1

Rectifier

X-ray radiationInterelectrode capacitances

Rectifier peak inverse voltage: 880 V
Rectifier nominal output current: 6 A
Rectifier peak forward current: 10 A
Rectifier forward voltage drop: 15 V
Rectifier warm-up time: 60 s

Representative of two identical gas-filled paths; application rating 6 A per valve and published Ia max 3 A per anode.

Section 2

Rectifier

X-ray radiationInterelectrode capacitances

Rectifier peak inverse voltage: 880 V
Rectifier nominal output current: 6 A
Rectifier peak forward current: 10 A
Rectifier forward voltage drop: 15 V
Rectifier warm-up time: 60 s

Second physical rectifier section added to represent the full-wave/double-anode structure.

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.

Data set 01

1999 Philips 0-D

Published operating points and test conditions from this source.

SECTION 1

Rectifier

Other

Maximum RMS anode supply voltage
285 V
Minimum RMS anode supply voltage
130 V
Maximum average anode current per anode
3 A
Permitted mercury/ambient temperature
-55 to 75 degC
DC output current
6 A

SECTION 2

Rectifier

Other

Maximum RMS anode supply voltage
285 V
Minimum RMS anode supply voltage
130 V
Maximum average anode current per anode
3 A
Permitted mercury/ambient temperature
-55 to 75 degC
DC output current
6 A