{"type_number":"IW3","canonical_url":"https://tubeofile.com/tubes/IW3","manufacturer":"Mullard","tube_type_key":"rectifier","tube_type_display_name":"Rectifier","base_name":"B4","description":"Indirectly-heated full-wave vacuum rectifier with 4 V heater. B4 base (4-pin). Mullard design for use in AC mains receivers. Intended for use with the PenA4 output pentode in Mullard receiver designs.","is_directly_heated":false,"completeness":"medium","notes":["The PenA4 datasheet specifies that PenA4 should only be used with the IW4/350 rectifier, but IW3 is a related type.","Brans lists equivalents: DW15, IW4.","Valve_Equivalents lists IW3 as 'Double Diode' on B4 base with 4 V heater.","Full-wave rectifier with two anodes.","Peak Inverse Voltage is not explicitly stated in the Mazda IW3 datasheet; PIV=849 V is derived from the standard full-wave capacitor-input relation PIV = 2 × √2 × Va_max (300 Vrms). Matches the convention used for AZ12, UU4, UU5, EZ41 in this repo.","Ia_max corrected from 60 mA (per-anode) to 120 mA (total DC output) — repo convention uses output DC current throughout. Per-anode rating per r-type.org was 60 mA."],"references":["https://tdsl.duncanamps.com/show.php?des=IW3","https://www.radiomuseum.org/tubes/?tube=IW3"],"source_urls":{"r_type":null,"tdsl":"https://tdsl.duncanamps.com/show.php?des=IW3","radiomuseum":"https://www.radiomuseum.org/tubes/tube_iw3.html"},"raw_equivalents":["IW4","DW15"],"equivalents":[],"similar":[{"type_number":"AZ11","reason":"Philips 4 V full-wave rectifier — different base, not pin-compatible","has_detail_page":true},{"type_number":"IW4/350","reason":"Related rectifier variant — similar application","has_detail_page":true}],"pins":[{"pin_number":"1","function":"Anode 1","function_code":"a1","notes":null},{"pin_number":"2","function":"Heater / Cathode","function_code":"h","notes":null},{"pin_number":"3","function":"Heater","function_code":"h","notes":null},{"pin_number":"4","function":"Anode 2","function_code":"a2","notes":null}],"specs":[{"key":"Vh","display_name":"Heater Voltage","value":"4","numeric_value":"4","unit":"V","param_group":"heater"},{"key":"Ah","display_name":"Heater Current","value":"1","numeric_value":"1","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":"300","numeric_value":"300","unit":"V","param_group":"absolute_max"},{"key":"PIV","display_name":"Peak Inverse Voltage","value":"849","numeric_value":"849","unit":"V","param_group":"rectifier"},{"key":"Idc_max","display_name":"Max DC Output Current (total, not per-anode)","value":"120","numeric_value":"120","unit":"mA","param_group":"rectifier"}]}],"synced_at":"2026-04-08T07:56:24.019Z"}