{"type_number":"673","canonical_url":"https://tubeofile.com/tubes/673","manufacturer":"RCA","tube_type_key":"rectifier","tube_type_display_name":"Rectifier","base_name":"B4","description":"Half-wave mercury-vapor rectifier designed for high-voltage, high-current industrial and transmitter power supply applications. Large metal-shell tube with Super Jumbo 4-pin bayonet base and top-cap anode. Filament-type cathode rated at 5 V. RCA design.","is_directly_heated":true,"completeness":"high","notes":["Mercury-vapor rectifier — requires a 30-second minimum warm-up at rated filament voltage before applying anode voltage.","Condensed-mercury temperature must be maintained between 20-60°C (or 20-50°C for reduced ratings). External heating or cooling may be required.","Peak inverse voltage rating is 10,000 V (20-60°C range) or 15,000 V (20-50°C range).","Tube voltage drop approximately 10 V.","Used in half-wave, full-wave, and polyphase rectifier circuits for transmitter power supplies."],"references":["https://frank.pocnet.net/sheets/049/6/673.pdf"],"source_urls":{"r_type":null,"tdsl":null,"radiomuseum":"https://www.radiomuseum.org/tubes/tube_673.html"},"raw_equivalents":[],"equivalents":[],"similar":[{"type_number":"866A","reason":"Another mercury-vapor half-wave rectifier — different ratings and base","has_detail_page":true}],"pins":[{"pin_number":"1","function":"No Connection","function_code":"nc","notes":null},{"pin_number":"2","function":"Filament, Cathode","function_code":"f","notes":null},{"pin_number":"3","function":"Filament","function_code":"f","notes":null},{"pin_number":"4","function":"No Connection","function_code":"nc","notes":null},{"pin_number":"TC","function":"Anode (top cap)","function_code":"a","notes":null}],"specs":[{"key":"Vh","display_name":"Heater Voltage","value":"5","numeric_value":"5","unit":"V","param_group":"heater"},{"key":"Ah","display_name":"Heater Current","value":"10","numeric_value":"10","unit":"A","param_group":"heater"}],"sections":[{"section_number":1,"section_label":"Rectifier (half-wave, in-phase, 20-60°C)","tube_type_key":"rectifier","specs":[{"key":"PIV","display_name":"Peak Inverse Voltage","value":"10000","numeric_value":"10000","unit":"V","param_group":"rectifier"},{"key":"Vdrop","display_name":"Voltage Drop (typical)","value":"10","numeric_value":"10","unit":"V","param_group":"rectifier"},{"key":"Idc_max","display_name":"Max DC Output Current (total, not per-anode)","value":"1750","numeric_value":"1750","unit":"mA","param_group":"rectifier"},{"key":null,"display_name":"Peak Anode Current (max)","value":"7000","numeric_value":"7000","unit":"mA","param_group":null}]}],"synced_at":"2026-04-08T07:51:20.636Z"}