TUBE: 12B4A (12B4-A)
SOURCE FILE: sheets/049/1/12B4A.pdf
MANUFACTURER: RCA (Radio Corporation of America, Harrison, New Jersey)
YEAR: May 1, 1955 (TENTATIVE DATA)
PAGES: 2

===== PAGE 1 =====
RCA 12B4-A
LOW-MU TRIODE
9-PIN MINIATURE TYPE
Intended for use in equipment having series heater-string arrangement

GENERAL DATA
Electrical:
Heater, for Unipotential Cathode:
  Heater arrangement        Series    Parallel
  Voltage                   12.6      6.3      ac or dc volts
  Current                   0.300     0.600    amp
  Warm-up time (Average)     -        11       sec

Direct Interelectrode Capacitances (Approx.):
  Grid to plate                              4.8   uuf
  Grid to cathode and heater                 5     uuf
  Plate to cathode and heater                1.5   uuf

Characteristics, Class A1 Amplifier:
  Plate Voltage                              150   volts
  Grid Voltage                               -17.5 volts
  Amplification Factor                       6.5
  Plate Resistance (Approx.)                 1030  ohms
  Transconductance                           6300  umhos
  Plate Current                              34    ma
  Grid Voltage (Approx.) for plate current of 200 uamp.   -32  volts
  Plate Current for grid voltage of -23 volts            9.6  ma

Mechanical:
  Mounting Position: Any
  Maximum Overall Length: 2-5/8"
  Maximum Seated Length: 2-3/8"
  Length, Base Seat to Bulb Top (Excluding tip): 2" +/- 3/32"
  Maximum Diameter: 7/8"
  Bulb: T-6-1/2
  Base: Small-Button Noval 9-Pin (JETEC No.E9-1)
  Basing Designation for BOTTOM VIEW: 9AG
    Pin 1 - Cathode
    Pin 2 - Grid
    Pin 3 - Heater Mid-Tap
    Pin 4 - Heater
    Pin 5 - Heater
    Pin 6 - No Connection
    Pin 7 - Grid
    Pin 8 - No Connection
    Pin 9 - Plate
  (With external shield JETEC No.315 connected to cathode.)

===== PAGE 2 =====
AMPLIFIER - Class A1
Maximum Ratings, Design-Center Values:
  PLATE VOLTAGE                              550   max. volts
  GRID VOLTAGE: Negative bias value          50    max. volts
  PLATE DISSIPATION                          5.5   max. watts
  PEAK HEATER-CATHODE VOLTAGE:
    Heater negative w.r.t. cathode           200   max. volts
    Heater positive w.r.t. cathode           200*  max. volts  (*dc component must not exceed 100 V)
Maximum Circuit Values:
  Grid-Circuit Resistance:
    For fixed-bias operation                 0.47  max. megohm
    For cathode-bias operation               2.2   max. megohms

VERTICAL DEFLECTION AMPLIFIER
Maximum Ratings, Design-Center Values Except as Noted (525-line, 30-frame system):
  DC PLATE VOLTAGE                           550   max. volts
  PEAK POSITIVE-PULSE PLATE VOLTAGE (Abs. max.)  1000  max. volts
  PEAK NEGATIVE-PULSE GRID VOLTAGE           250   max. volts
  CATHODE CURRENT: Peak                      105   max. ma
                   Average                   30    max. ma
  PLATE DISSIPATION                          5.5   max. watts
  PEAK HEATER-CATHODE VOLTAGE:
    Heater negative w.r.t. cathode           200   max. volts (also 200 total dc+peak)
Maximum Circuit Values:
  Grid-Circuit Resistance: cathode-bias      2.2   max. megohms