Characteristics
| Base | UX-Base (4 pins, 2 thick), A4-72 Medium 4-Pin Bayonet Base |
| Type | Triode Power Output |
| Filament | Vf = 2.5 Volts, If = 1.5 Ampere, Direct Specified voltage AC/DC |
| Identical | 145, A245, ER45, EX645, UX245, PH245, G45, AX-245, CL-45, RayX-245, RYB245, NU-45, C-245, SX245, MX245, L45, X245, P245, T-45, Z-45, R45 Rogers, NX-245, TS245, TX245, 445, 245/C, ER245, DX245, PA245, AC45, TX-45, VX245, 245, CX345 |
| Similar | Different Shape: M45, PM245 Slightly Different: 38045, FX245, U245, VT-45 Different Quality: 536A Boonton, CV610 |
| Predecessor | 71A |
| Successor | 2A3, VT-52 |
Maximum Ratings
| Max Anode Voltage (Pin 2) | 275 Volts |
| Max Anode Dissipation | 10 Watts |
Pin Layout
| Pin | Function |
| 1 | Filament |
| 2 | Anode |
| 3 | Grid |
| 4 | Filament |