{"type_number":"5Y4G","canonical_url":"https://tubeofile.com/tubes/5Y4G","manufacturer":"RCA","tube_type_key":"rectifier","tube_type_display_name":"Rectifier","base_name":"Octal","description":"Full-wave high-vacuum rectifier, indirectly heated. Same electrical characteristics as the 5Y3-G but with indirectly heated cathode construction. Designed for power supply applications with DC output current up to 125 mA.","is_directly_heated":false,"completeness":"high","notes":["Indirectly heated rectifier — unlike the directly heated 5Y3, the 5Y4G has a separate cathode heated by the filament. This provides a natural delay before the tube conducts, protecting filter capacitors.","RCA datasheet states 'The 5Y4-G is the same as the 5Y3-G except for the following items' — mechanically different (indirectly heated) but same electrical ratings.","5Y4-G has pin 5 = Plate No.1, pin 3 = Plate No.2. The 5Y4-GT variant uses a different pinout: pin 3 = Plate No.2, pin 5 = Plate No.1.","The 5Y4-GT uses a 6-pin intermediate-shell Octal base (JETEC B6-8L or B6-48).","Raytheon lists 5V4G, 5Y3GT, 5W4GT as substitutes — verify ratings and pinout before substituting."],"references":["https://frank.pocnet.net/sheets/049/5/5Y4G.pdf","https://tdsl.duncanamps.com/show.php?des=5Y4G"],"source_urls":{"r_type":null,"tdsl":"https://tdsl.duncanamps.com/show.php?des=5Y4G","radiomuseum":"https://www.radiomuseum.org/tubes/tube_5y4g.html"},"raw_equivalents":["5Y4GT","CV1857"],"equivalents":[],"similar":[{"type_number":"5V4G","reason":"Indirectly heated rectifier on same Octal base but higher voltage rating (500V RMS vs 350V) and different pinout — not a drop-in","has_detail_page":false},{"type_number":"5Y3GT","reason":"Same electrical ratings but directly heated (filament cathode) — same Octal base but different construction. The 5Y4G has slower warm-up due to indirect heating.","has_detail_page":false}],"pins":[{"pin_number":"1","function":"No Connection","function_code":"nc","notes":null},{"pin_number":"2","function":"No Connection","function_code":"nc","notes":null},{"pin_number":"3","function":"Anode 2 (Plate 2)","function_code":"a2","notes":null},{"pin_number":"4","function":"No Connection","function_code":"nc","notes":null},{"pin_number":"5","function":"Anode 1 (Plate 1)","function_code":"a1","notes":null},{"pin_number":"6","function":"No Connection","function_code":"nc","notes":null},{"pin_number":"7","function":"Heater","function_code":"h","notes":null},{"pin_number":"8","function":"Heater","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":"2.0","numeric_value":"2","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":"350","numeric_value":"350","unit":"V","param_group":"absolute_max"},{"key":"PIV","display_name":"Peak Inverse Voltage","value":"1400","numeric_value":"1400","unit":"V","param_group":"rectifier"},{"key":"Vdrop","display_name":"Voltage Drop (typical)","value":"60","numeric_value":"60","unit":"V","param_group":"rectifier"},{"key":"C_max","display_name":"Max C-input Filter Capacitor","value":"20","numeric_value":"20","unit":"µF","param_group":"rectifier"},{"key":"Ia_max","display_name":"DC Output Current (max)","value":"125","numeric_value":"125","unit":"mA","param_group":"rectifier"},{"key":"Ia_peak","display_name":"Peak Anode Current (surge)","value":"440","numeric_value":"440","unit":"mA","param_group":"rectifier"}]}],"synced_at":"2026-04-07T12:13:16.845Z"}