35W4
35W4 has no equivalent designation confirmed by the archive. Completed sales put the typical price at $10.36 per tube.
Description
The 35W4 is a miniature, indirectly heated half-wave rectifier tube with a 150 mA heater. It consists of a half-wave rectifier unit with an indirectly heated cathode, the cathode being insulated from the heater. The tube is mounted in a standard T5-1/2 bulb and is based with a B7G B.V.A. Standard base.
Construction and Basing
The 35W4 has a heater tap that enables a dial lamp to be operated across a portion of the heater. The basing connections are: Pin 1 No Connection, Pin 2 No Connection, Pin 3 Heater, Pin 4 Heater, Pin 5 Anode, Pin 6 Heater Tap, Pin 7 Cathode. The dial lamp heater section is between pins 4 and 6. The tube is designed for use with a dial lamp rated at 6.3 volts and 0.15 ampere.
Ratings
The nominal heater voltage on pins 3 and 4 is 35 volts without a dial lamp and 32 volts with a dial lamp. The nominal lamp section voltage on pins 4 and 6 is 7.5 volts without a dial lamp and 5.5 volts with a dial lamp. Heater current is 0.15 ampere, with the Brimar datasheet giving a tolerance of not more than 5% variation from the rated value at any time. The maximum DC heater-cathode potential is 330 volts. The maximum peak inverse voltage is 700 volts, and the maximum peak anode current is 600 mA.
With a condenser input filter, the maximum AC anode voltage (R.M.S.) is 250 volts, the minimum effective limiting resistance is 120 ohms, and the maximum reservoir condenser is 32 mfd. The maximum DC output current is 100 mA without a dial lamp, 60 mA with a dial lamp only, and 90 mA with a dial lamp and resistor. The Brimar datasheet recommends that for operation with a dial lamp, if the rectified DC load exceeds 60 mA, an additional shunting resistor across the lamp and pins 4 and 6 is essential.
Physical Dimensions
The maximum overall length is 2-5/8 inches, maximum diameter is 3/4 inch, and maximum seated height is 2-3/8 inches.
Application Notes
The 35W4 is intended for use in series with other valves having a similar heater current, such as in AC/DC equipment. The Brimar datasheet states that ratings above 117 volts R.M.S. input may not be applicable to 35W4s of other manufacturers.
| Measure | Per tube |
|---|---|
| Median | $10.36 |
| Typical range (25th–75th) | $5.87 – $20.99 |
| Most sales (10th–90th) | $5.00 – $105.73 |
| Extremes incl. outliers | $1.43 – $129.00 |
| Completed sales | 17 |
| Brand | Median | Range | Sales |
|---|---|---|---|
| RCA | $21.49 | $13.97 – $105.73 | 3 |
| Condition | Median | Sales |
|---|---|---|
| NOS | $8.98 | 9 |
| used | $21.97 | 6 |
Per-tube prices from completed sales, 2023-05-31 to 2026-09-11. Matched pairs and quads are divided out. See the price index for how these move over time.
Original manufacturer datasheets for 35W4, hosted by Frank Philipse's Electron Tube Data sheets.
| Manufacturer | Designation | Datasheet |
|---|---|---|
| Brimar | 35W4 | PDF (572 KB) |
| Mazda-Belvu | 35W4 | PDF (468 KB) |
| General Electric | 35W4 | PDF (312 KB) |
| Tung-Sol | 35W4 | PDF (156 KB) |
| RCA (HB3) | 35W4 | PDF (150 KB) |
| Brimar | 35W4 | PDF (52 KB) |
Documents held here and used to write this page.
- BRIMAR
1 further designation appears alongside 35W4 in the literature but below the evidence threshold used here, so it is not listed as equivalent.