Tube cross-reference
5866 alternatives, equivalents, and replacements
Review exact electrical variations and directional substitutions recorded for the 5866 specialized - ignitron. Compare core specifications and verify every restriction before using a replacement.
Exact variations of 5866
These designations belong to the same electrical variation group. Their names may differ because of international standards, manufacturing tolerances, or materials, but they are recorded as electrically equivalent—not merely substitutes.
TB25300 Power - Triode (over 1000V 100W)
- Base
- Not recorded
- Socket
- B5F
- Base pins
- Not recorded
- Sections
- 1
- Heater voltage
- 6.3 V
- Heater current
- 5.4 A
Verify before substituting
Matching a base or heater voltage is not enough to prove that two tubes are interchangeable. Check pin connections, heater current, maximum ratings, bias requirements, warm-up behavior, and the equipment manufacturer’s service documentation before making a substitution.
View the complete 5866 specifications →