Rectifier - Half Wave ·Rectifier
Indirectly heated half-wave rectifier for three-way portable receiver supplies. Its 117 V heater is designed for line-series operation while providing modest rectified DC output.
The 117Z4GT is a half-wave high-vacuum rectifier tube designed primarily for service in three-way portable radio receivers. It features a coated unipotential cathode and a high-voltage heater designed for direct operation across a standard 117-volt AC or DC power line, eliminating the need for a series dropping resistor or power transformer in line-operated equipment.
The 117Z4GT is constructed in a T-9 glass bulb envelope with an intermediate shell 6-pin octal base. The physical dimensions of the tube are compact to facilitate installation in portable equipment:
The tube can be mounted and operated in any position.
The electrical connections are arranged according to the 5AA basing diagram. Viewed from the bottom of the tube, the pin assignments are as follows:
Pins 4 and 6 are omitted from the physical base structure, resulting in a 6-pin configuration on the standard octal footprint.
The heater of the 117Z4GT is designed to run directly on line voltage, minimizing auxiliary power supply components. The electrical ratings, interpreted according to the RMA Standard M8-210, establish the safe operating boundaries for the device:
| Parameter | Value | Unit |
|---|---|---|
| Heater Voltage (AC or DC) | 117 | V |
| Heater Current | 0.040 (40) | A (mA) |
| Maximum AC Plate Voltage (RMS) | 117 | V |
| Maximum Peak Inverse Plate Voltage | 350 | V |
| Maximum Steady-State Peak Plate Current | 540 | mA |
| Maximum DC Heater-Cathode Potential | 175 | V |
During operation, the internal resistance of the tube results in a voltage drop. The nominal tube voltage drop is 22.5 Volts when conducting a direct current of 180 mA.
In typical applications, the 117Z4GT operates as a half-wave rectifier supplying power to a condenser-input filter network. Under these conditions, the typical operating parameters are:
When designing the rectifier circuit, the choice of the input filter capacitor is critical for tube longevity. The minimum specified total effective plate supply impedance of 30 Ohms must be maintained to limit peak inrush and steady-state currents. If the input filter condenser has a capacitance larger than 40 µF, it may be necessary to add additional series plate supply impedance to protect the cathode from excessive peak current demands.
The 117Z4GT is a specialized, line-voltage-operated half-wave high-vacuum rectifier. By utilizing a 117 V, 40 mA heater, it allows direct line-power rectification without the bulk and heat of dropping resistors or step-down transformers, making it highly suitable for compact three-way portable receivers. Housed in a T-9 glass envelope with a 6-pin octal base (5AA basing), it supports any mounting orientation. Under typical operating conditions with a condenser-input filter, it delivers up to 90 mA of DC output current from a 117 V RMS supply, provided that a minimum plate supply impedance of 30 Ohms is maintained and filter capacitance limits are respected.
International Octal
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
Published ratings/characteristics promoted where semantically applicable.
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
117 V
HalfWave
Forward current at published voltage drop
180 mA
VoltageDrop=2.5V
Data set 02
Published operating points and test conditions from this source.
AC Plate Voltage RMS
117 V
CapacitorInputFilter
Effective Plate Supply Impedance
30 ohm
CapacitorInputFilter
Heater Voltage (Ac Or Dc)
117 V
Max. Ac Plate Voltage
117 V
Max. Dc Heater Cathode Potential
175 V
Max., Peak Inverse Plate Voltage
350 V
Ac Plate Voltage (Rms)
117 V
Dc Output Current
90 mA
Min., Total Effective Plate Supply Impedancea
20 ohm