{"type_number":"82","canonical_url":"https://tubeofile.com/tubes/82","manufacturer":null,"tube_type_key":"rectifier","tube_type_display_name":"Rectifier","base_name":"UX4","description":"Full-wave mercury-vapour rectifier with directly heated (coated filament) cathode. Designed for AC-operated receivers requiring good voltage regulation. Uses UX4 base. Very low and nearly constant voltage drop (~15V) regardless of load current, unlike high-vacuum rectifiers. Requires mercury temperature operating range of 24-60 degrees C and controlled warm-up before applying B+ voltage.","is_directly_heated":true,"completeness":"high","notes":["Tung-Sol datasheet (1940) confirms: full-wave mercury vapor rectifier, 2.5V/3.0A coated filament, 4C (UX4) base.","Mercury-vapour rectifier: voltage drop is approximately 15V and remains nearly constant regardless of load current.","CRITICAL: Mercury-vapour tubes require a minimum warm-up period of 30-60 seconds before applying B+ voltage. Applying plate voltage to a cold mercury-vapour rectifier causes cathode stripping and rapid tube failure.","Mercury temperature operating range: 24-60 degrees C. Below this range, mercury condensation can cause arc-back.","Rectifier reference confirms: Vdrop=15V, max DC output=115 mA, max AC voltage=450V RMS per plate.","GE Essential Characteristics confirms: 2.5V/3.0A filament, 4C base, full-wave mercury-vapour rectifier.","MIL-HDBK-213A lists type 82 as mercury vapor rectifier (full wave).","With condenser input filter: effective plate supply impedance is 50 ohms per plate.","With choke input filter: max AC plate voltage increases to 550V RMS, value of input choke minimum 6 henrys.","When filter condensers larger than 40 uF are used, additional plate supply impedance may be necessary.","The 82 and 83 may be operated with plates connected in parallel for equalizing current distribution.","82V is a substitute per Sams substitution data."],"references":["https://frank.pocnet.net/sheets/127/8/82.pdf"],"source_urls":{"r_type":null,"tdsl":"http://tdsl.duncanamps.com/show.php?des=82","radiomuseum":"https://www.radiomuseum.org/tubes/tube_82.html"},"raw_equivalents":["CV1773","VT-82"],"equivalents":[],"similar":[{"type_number":"80","reason":"Same UX4 base and similar form factor, high-vacuum type — much higher voltage drop (60V vs 15V) but no warm-up requirement and longer life","has_detail_page":true},{"type_number":"83","reason":"Same UX4 base, same mercury-vapour technology, but 5V/3A filament — higher current rating (225 mA vs 115 mA) and not filament-compatible","has_detail_page":true}],"pins":[{"pin_number":"1","function":"Anode 1 (Plate 1)","function_code":"a1","notes":null},{"pin_number":"2","function":"Filament","function_code":"h","notes":null},{"pin_number":"3","function":"Anode 2 (Plate 2)","function_code":"a2","notes":null},{"pin_number":"4","function":"Filament","function_code":"h","notes":null}],"specs":[{"key":"Vh","display_name":"Heater Voltage","value":"2.5","numeric_value":"2.5","unit":"V","param_group":"heater"},{"key":"Ah","display_name":"Heater Current","value":"3.0","numeric_value":"3","unit":"A","param_group":"heater"}],"sections":[{"section_number":1,"section_label":"Rectifier","tube_type_key":"rectifier","specs":[{"key":"Va_max","display_name":"Anode Voltage (max)","value":"450","numeric_value":"450","unit":"V","param_group":"absolute_max"},{"key":"PIV","display_name":"Peak Inverse Voltage","value":"1550","numeric_value":"1550","unit":"V","param_group":"rectifier"},{"key":"Vdrop","display_name":"Voltage Drop (typical)","value":"15","numeric_value":"15","unit":"V","param_group":"rectifier"},{"key":"Ia_peak","display_name":"Peak Anode Current (surge)","value":"345","numeric_value":"345","unit":"mA","param_group":"rectifier"},{"key":"Idc_max","display_name":"Max DC Output Current (total, not per-anode)","value":"115","numeric_value":"115","unit":"mA","param_group":"rectifier"},{"key":"ri","display_name":"Internal Resistance","value":"50","numeric_value":"50","unit":"Ω","param_group":"rectifier"}]}],"synced_at":"2026-04-08T07:53:49.846Z"}