17AY3 — Half-Wave Vacuum Rectifier

The 17AY3 and 17AY3A are Novar-type, heater-cathode half-wave vacuum rectifiers designed primarily for television damper service. These tubes are electrically identical to the 6AY3 and 6AY3B respectively, with the exception of their heater characteristics and ratings.

Mechanical Construction and Pinout

The 17AY3 and 17AY3A utilize a Novar T-9 construction but differ in their physical dimensions and base configurations. The 17AY3A is identical to the 17AY3 except that it features a base with an exhaust tip at the bottom and a shorter bulb.

Physical Dimensions

• 17AY3:
  • Base: Novar Button 9 Pin, E9-75
  • Outline: 9-86
  • Maximum Diameter: 1.188 inches
  • Maximum Seated Height: 3.030 inches
  • Maximum Overall Height: 3.410 inches
• 17AY3A:
  • Base: Novar Button 9 Pin, E9-89 (with exhaust tip on base)
  • Maximum Diameter: 1.188 inches
  • Maximum Seated Height: 2.625 inches
  • Maximum Overall Height: 3.005 inches

Pin Connections (9HP Basing)

Both variants share the 9HP basing configuration. Pins designated as Internal Connection (IC) must not be used as circuit tie points.

Heater and Electrical Characteristics

The heater is designed for operation in series-string receiver configurations, featuring a controlled warm-up time.

• Heater Voltage (AC or DC): 16.8 V
• Heater Current: 0.450 A (with an allowable tolerance of 0.030 A)
• Average Warm-up Time: 11 seconds

Direct Interelectrode Capacitances

Measured without an external shield, the direct interelectrode capacitances of the tube are:

• Heater to Cathode: 2.8 pF
• Plate to Cathode and Heater: 6.5 pF
• Cathode to Plate and Heater: 9.0 pF

Maximum Ratings and Operating Limits

The ratings for the 17AY3 and 17AY3A are established under the Design Maximum Rating System for television damper service.

Damper Service Ratings

• Peak Inverse Plate Voltage (Max.): 5000 V
  • Note on Peak Inverse Voltage: This limit applies to operation in a 525-line, 30-frame television system where the duty cycle of the voltage pulse does not exceed 15% of one horizontal scanning cycle.
• Plate Dissipation (Max.): 6.3 W
• Steady State Peak Current (Max.): 1100 mA
• DC Plate Current (Max.): 175 mA

Heater-Cathode Voltage Limits

• Heater Negative with Respect to Cathode:
  • DC Limit: 900 V
  • Total DC and Peak Limit: 5000 V
• Heater Positive with Respect to Cathode:
  • DC Limit: 100 V
  • Total DC and Peak Limit: 300 V

Technical Summary

The 17AY3 and 17AY3A are specialized Novar half-wave rectifiers engineered for television damper service. Operating with a 16.8 V, 450 mA heater, they provide robust high-voltage isolation, supporting peak inverse plate voltages up to 5000 V and peak heater-cathode voltages up to 5000 V (heater negative). The 17AY3A offers a more compact physical envelope through its E9-89 base with a bottom exhaust tip, while maintaining identical electrical ratings and 9HP pinout configuration to the standard 17AY3.