{"type_number":"GZ31","canonical_url":"https://tubeofile.com/tubes/GZ31","manufacturer":"Mullard","tube_type_key":"rectifier","tube_type_display_name":"Rectifier","base_name":"Octal","description":"Full-wave rectifier with indirectly heated cathode on Octal base. Mullard/Philips designation. Equivalent to the American 5AS4/5AS4A. Designed for power supply applications in radio and audio equipment.","is_directly_heated":false,"completeness":"high","notes":["The GZ31 is the Mullard/Philips designation for a full-wave rectifier. The 5AS4A is the American RETMA equivalent.","Indirectly heated cathode with 5V heater. Sams lists 5U4G as a substitute.","Soviet equivalent 5C3S (5Ц3С) covers both 5U4G and GZ31 according to the Russian equivalents reference.","Peak Inverse Voltage is not explicitly stated in the Mullard/Philips GZ31 datasheet; PIV=990 V is derived from the standard full-wave capacitor-input relation PIV = 2 × √2 × Va_max (350 Vrms). Matches the convention used for AZ12, UU4, UU5, EZ41 in this repo.","Vdrop = 50V per references/rectifier_reference.json entry for 5AS4-A ('improved 5U4') — GZ31 is the Mullard/Philips designation for this same indirectly-heated 5V/2A octal rectifier (description in this file confirms the 5AS4/5AS4A equivalence)."],"references":["https://frank.pocnet.net/sheets/049/5/5AS4.pdf","https://tdsl.duncanamps.com/show.php?des=GZ31"],"source_urls":{"r_type":null,"tdsl":"https://tdsl.duncanamps.com/show.php?des=GZ31","radiomuseum":"https://www.radiomuseum.org/tubes/tube_gz31.html"},"raw_equivalents":["5AS4","5AS4A","CV3440"],"equivalents":[],"similar":[{"type_number":"5U4G","reason":"Russian equivalents reference lists 5C3S as equivalent to both 5U4G and GZ31 — similar full-wave rectifier but directly heated, different characteristics","has_detail_page":true},{"type_number":"GZ32","reason":"Similar Mullard rectifier on Octal base but different voltage/current ratings","has_detail_page":true},{"type_number":"GZ34","reason":"Higher-current Mullard rectifier (5AR4) on Octal base — not directly interchangeable due to higher current ratings","has_detail_page":true}],"pins":[{"pin_number":"1","function":"No Connection","function_code":"nc","notes":null},{"pin_number":"2","function":"Heater","function_code":"h","notes":null},{"pin_number":"3","function":"Anode 1","function_code":"a1","notes":null},{"pin_number":"4","function":"Anode 2","function_code":"a2","notes":null},{"pin_number":"5","function":"No Connection","function_code":"nc","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":"Cathode","function_code":"k","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":"2","numeric_value":"2","unit":"A","param_group":"heater"}],"sections":[{"section_number":1,"section_label":"Full-Wave 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":"990","numeric_value":"990","unit":"V","param_group":"rectifier"},{"key":"Vdrop","display_name":"Voltage Drop (typical)","value":"50","numeric_value":"50","unit":"V","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":"2026-04-09T05:18:44.742Z"}