Diode (NOT rectifier) ·Diode-Diode
Twin high-vacuum diode for detector, discriminator, and general signal rectification, using a 12.6 V heater suitable for series-fed receiving equipment.
The 12H6 is a metal-envelope twin diode vacuum tube designed for detector, low-current rectifier, or limiter applications. It features two independent diode units in a single envelope, sharing a common heater but having separate cathode connections. The 12H6 is electrically identical to the 6H6 twin diode, with the sole exception of its heater characteristics and ratings, which are designed for 12.6-volt electrical systems.
The 12H6 is constructed as a metal tube, indicated by its bold-face designation in standard classification tables. It utilizes an octal base with a 7Q pin connection diagram and is housed in an 8-5 outline drawing configuration.
The tube contains two separate, indirectly heated diode sections. Because each diode has its own independent cathode, the two sections can be operated in separate circuits with different cathode potentials, subject to heater-to-cathode voltage limitations.
The 12H6 uses an octal base requiring a 7Q connection arrangement. Viewed from the bottom of the base, the pin assignments are as follows:
Pin 6 has no connection shown in the standard 7Q diagram.
The primary distinction of the 12H6 compared to the 6H6 is its heater, which is rated for operation in 12.6-volt systems (either alternating or direct current).
| Parameter | Value |
|---|---|
| Heater Voltage (AC or DC) | 12.6 V |
| Heater Current | 0.150 A |
| Cathode Type | Indirectly heated (Htr) |
From these values, the nominal heater power consumption can be calculated:
When operated as a half-wave rectifier, each diode section of the 12H6 is subject to specific maximum ratings and typical operating limits. The electrical characteristics and ratings per plate include:
These ratings define the safe operating envelope for the tube in power rectification and signal detection. The low maximum DC output current of 8 mA per plate indicates that the 12H6 is intended for signal detection, automatic volume control (AVC), or low-current bias supplies rather than high-power mains rectification.
The 12H6 is a metal-envelope, octal-base twin diode featuring two independent diode sections with separate cathodes and a shared 12.6 V, 0.150 A heater. It is identical in design and electrical performance to the 6H6, except for its heater configuration. In half-wave rectifier service, each plate supports a maximum RMS supply voltage of 150 V, a peak inverse voltage of 420 V, a peak current of 48 mA, and a continuous DC output current of 8 mA, with a typical tube voltage drop of 11 V at 16 mA.
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.
2 physical sections, each with unique specifications.
Section 1
Representative row for two identical diode sections.
Section 2
No fixed ratings are recorded for this section.
Physical diode section added in approved section-structure reconciliation.
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.
RMS supply voltage per plate
150 V
HalfWave
Forward current at published voltage drop
16 mA
VoltageDrop=11V
Data set 02
Published operating points and test conditions from this source.
Heater voltage
12.6 V
Heater current
150 mA
Peak inverse voltage
420 V
EachDiode
Peak plate current
50 mA
EachDiode
Average rectified current
8 mA
EachDiode
Plate-to-cathode capacitance
3 pF
EachDiode