45A5
45A5 is also designated UL41.
Description
The 45A5 is a power amplifier pentode with a glass bulb and a coated unipotential cathode. It uses an E8-30 base.
Physical Characteristics
The maximum overall length is 2-31/32 inches (76 mm), the maximum seated height is 2-23/32 inches (69 mm), and the maximum diameter is 7/8 inch (22 mm). The tube can be mounted in any position.
Ratings
The heater is rated at 45 volts and 0.1 amps. Maximum ratings include a plate voltage of 250 volts, a plate dissipation of 9 watts, a grid No. 2 voltage of 250 volts, a grid No. 2 dissipation of 1.75 watts at zero signal and 4.0 watts at maximum signal, a cathode current of 75 mA, a grid No. 1 circuit resistance of 1 megohm, a voltage between heater and cathode of 150 volts, and an external resistance between heater and cathode of 20,000 ohms.
Electrical Characteristics
At a plate voltage of 200 volts, a grid No. 2 voltage of 200 volts, and a grid No. 1 voltage of -14.2 volts, the plate resistance is 24,000 ohms, the amplification factor of grid No. 2 with respect to grid No. 1 is 10, and the transconductance is 8,200 µmhos. The input capacitance is 11.0 μμF, the output capacitance is 8.3 μμF, and the plate to grid No. 1 capacitance is less than 1.0 μμF.
Base Connections
The heater is connected to pins 1 and 8, the plate to pin 2, grid No. 2 to pin 5, grid No. 1 to pin 6, and cathode and grid No. 3 to pin 7. Pins 3 and 4 serve as internal connections.
Source
The datasheet for the 45A5 is from JETEC release #1526, dated Oct. 10, 1955.
| Designation | Evidence | Confidence |
|---|---|---|
| UL41 | 42 independent documents | confirmed |
Equivalence is asserted only where the archive's own literature states it directly, in at least 40 separate documents. Tubes that merely substitute in some circuits are not listed here.
Original manufacturer datasheets for 45A5, hosted by Frank Philipse's Electron Tube Data sheets.
| Manufacturer | Designation | Datasheet |
|---|---|---|
| Philips | 45A5 | PDF (135 KB) |
| Philips | UL41 | PDF (576 KB) |
| Philips | UL41 | PDF (406 KB) |
| Philips | UL41 | PDF (395 KB) |
| Mazda-Belvu | UL41 | PDF (113 KB) |
| La Radiotechnique | UL41 | PDF (97 KB) |
Documents held here and used to write this page.
- UL 41 9 W output pentode (filed under UL41)
- MAXIMUM RATINGS (Design Centre Values)
1 further designation appears alongside 45A5 in the literature but below the evidence threshold used here, so it is not listed as equivalent.