{"type_number":"5U4G","canonical_url":"https://tubeofile.com/tubes/5U4G","manufacturer":null,"tube_type_key":"rectifier","tube_type_display_name":"Rectifier","base_name":"Octal","description":"Full-wave vacuum rectifier for medium-power equipment. Directly heated (filament cathode). Designed for use with center-tapped transformer in full-wave configuration, delivering up to 225 mA DC output with choke-input filter.","is_directly_heated":true,"completeness":"high","notes":["Directly heated (filament cathode) — observe heater warm-up time before applying B+ to protect the tube and filter capacitors.","Relatively high voltage drop (~44 V at 225 mA) compared to indirectly-heated rectifiers like 5AR4/GZ34 (~15 V). This provides natural 'soft start' characteristics valued in audio equipment.","Max DC output current depends on filter type: 225 mA with choke-input filter. With capacitor-input filter, a minimum series resistance (Rs) is required to limit peak current.","5U4GB is an improved version with higher ratings — not always a direct drop-in; verify pinout and ratings before substituting.","5931 (also designated 5U4WG) is the JAN military-grade ruggedized version — electrically identical but built for shock/vibration resistance and longer life. Physically larger and taller than standard 5U4G; check chassis clearance before substituting.","Pins 4 and 6 are the two anodes (plates) for full-wave center-tapped rectification. Pins 1, 3, 5, 7 have no connection."],"references":["http://tdsl.duncanamps.com/show.php?des=5U4G"],"source_urls":{"r_type":"http://www.r-type.org/exhib/aaa0071.htm","tdsl":"http://tdsl.duncanamps.com/show.php?des=5U4G","radiomuseum":"https://www.radiomuseum.org/tubes/tube_5u4g.html"},"raw_equivalents":["5U4","5U4GT","5931","CV575","CV1575","U52","VT-244","53KU","5U4GA","5U4GB","422A","5U4WG","CV841","5Z3P"],"equivalents":[{"type_number":"5Z3P","equivalence_type":"direct","notes":null}],"similar":[{"type_number":"5C3S","reason":"Soviet equivalent (5Ц3С) — same Octal base, pin-compatible, but verify heater current compatibility (3.0A)","has_detail_page":true},{"type_number":"5T4","reason":"Metal-envelope equivalent of 5U4 with same Octal base but verify compatibility in specific circuits","has_detail_page":true},{"type_number":"5X4","reason":"Electrically identical but different Octal pinout — plates on pins 3/5 vs 4/6","has_detail_page":true}],"pins":[{"pin_number":"1","function":"No Connection","function_code":"nc","notes":null},{"pin_number":"2","function":"Filament","function_code":"h","notes":null},{"pin_number":"3","function":"No Connection","function_code":"nc","notes":null},{"pin_number":"4","function":"Anode 2 (Plate 2)","function_code":"a2","notes":null},{"pin_number":"5","function":"No Connection","function_code":"nc","notes":null},{"pin_number":"6","function":"Anode 1 (Plate 1)","function_code":"a1","notes":null},{"pin_number":"7","function":"No Connection","function_code":"nc","notes":null},{"pin_number":"8","function":"Filament","function_code":"h","notes":null}],"specs":[{"key":"Vh","display_name":"Heater Voltage","value":"5.0","numeric_value":"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":"44","numeric_value":"44","unit":"V","param_group":"rectifier"},{"key":"C_max","display_name":"Max C-input Filter Capacitor","value":"40","numeric_value":"40","unit":"µF","param_group":"rectifier"},{"key":"Ia_peak","display_name":"Peak Anode Current (surge)","value":"800","numeric_value":"800","unit":"mA","param_group":"rectifier"},{"key":"Idc_max","display_name":"Max DC Output Current (total, not per-anode)","value":"225","numeric_value":"225","unit":"mA","param_group":"rectifier"}]}],"synced_at":"2026-04-08T07:50:47.714Z"}