1803 — Half-Wave High-Vacuum Rectifier

The 1803 is a directly heated, half-wave high-vacuum rectifier tube designed primarily for use in A.C. mains receivers. It provides rectification of alternating current to supply high-voltage direct current for radio receivers and similar electronic equipment.

Mechanical and Base Specifications

The 1803 is constructed with a glass envelope having a maximum overall length of 100 mm and a maximum diameter of 52 mm, excluding the base pins.

Depending on the specific manufacturing variant, the tube is available with different basing configurations:

• Base H 35: Utilizes connection reference 14 or base connection S V.
• Base A 35: Utilizes base connection S III.

Filament and Heating Data

The tube features a directly heated filament designed for low-voltage AC operation. The filament characteristics are as follows:

Maximum Ratings

To ensure reliable operation and prevent damage to the tube, the operating conditions must be kept within the specified maximum limits:

• Maximum A.C. Anode Voltage (No-Load Voltage): 500 V_RMS
• Maximum Rectified D.C. Current: 30 mA

Rectification Characteristics and Load Curves

The output performance of the 1803 varies depending on the applied A.C. input voltage (V_eff) and the current drawn by the load. The relationship between the rectified output voltage (V_a) and the load current (I_a) across its operating range of 0 to 30 mA is characterized by the following performance points:

• At V_eff = 300 V: The output voltage is approximately 410 V under no-load conditions (0 mA) and drops to approximately 310 V at the maximum rated current of 30 mA.
• At V_eff = 400 V: The output voltage is approximately 560 V at 0 mA and drops to approximately 440 V at 30 mA.
• At V_eff = 500 V: The output voltage is approximately 710 V at 0 mA and drops to approximately 570 V at 30 mA.

These values illustrate the internal resistance and voltage regulation of the rectifier under typical operating conditions up to its maximum current limit.

Technical Summary

The 1803 is a compact, half-wave high-vacuum rectifier tube designed for A.C. mains receivers. Operating with a directly heated 4.0 V, 0.6 A filament, it is capable of handling a maximum A.C. anode voltage of 500 V and delivering up to 30 mA of rectified D.C. current. Its physical dimensions of 100 mm by 52 mm and compatibility with H35 or A35 bases make it a standard component for low-power high-voltage rectification.