Voltage - Triode (single) ·Triode
Directly heated or receiving triode documented by the manufacturer; available source material does not establish a narrower functional category strongly enough for reassignment.
The 4242A is a triode described in the Standard Valves datasheet, using a directly heated filament cathode and published operating data.
Large 4-contact bayonet base
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
Explicit alternate/previous designation printed on 3B850A datasheet.
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.
Total emission
15 A
Published datasheet value
Grid-anode capacitance
13 pF
Published datasheet value
Anode-filament capacitance
4 pF
Published datasheet value
Grid-filament capacitance
65 pF
Published datasheet value
Maximum frequency for above ratings
6 MHz
Published datasheet value
Maximum direct grid current
50 mA
Published datasheet value
Data set 02
Published operating points and test conditions from this source.
Mutual conductance
4200 µS
Published characteristic; normalized from mA/V
Grid-anode capacity
13 pF
Published interelectrode capacitance
Maximum direct anode current
150 mA
Maximum safe operating rating
Data set 03
Published operating points and test conditions from this source.
Maximum frequency at full rating
6 MHz