{"type_number":"AZ50","canonical_url":"https://tubeofile.com/tubes/AZ50","manufacturer":"Philips","tube_type_key":"rectifier","tube_type_display_name":"Rectifier","base_name":"B4","description":"Directly heated high-vacuum full-wave rectifier by Philips, designed for high-current power supply applications in European AC mains equipment. Uses a 4V directly heated filament and a 4-pin B4 base. Introduced around 1939, it was the highest-current rectifier in the Philips/Miniwatt AZ family, capable of 300 mA DC output.","is_directly_heated":true,"completeness":"high","notes":["Directly heated (filament cathode) — observe heater warm-up time before applying B+. Filament is heated by AC per the datasheet ('direct by A.C.').","Operating conditions from the Philips datasheet (3 rated voltage columns): at 2×300 Veff: Io_max=300 mA, Rt_min=100 Ω, C_max=16 µF; at 2×400 Veff: Io_max=275 mA, Rt_min=150 Ω, C_max=32 µF; at 2×500 Veff: Io_max=250 mA, Rt_min=200 Ω, C_max=64 µF. Idc_max=300 mA is the rated DC output (at 2×300 V); Va_max=500 V and C_max=64 µF are from the 2×500 V column.","Peak Inverse Voltage is not explicitly stated in the datasheet; PIV=1414 V is derived from the standard full-wave relation PIV = 2 × √2 × Va_max (500 Vrms). Matches the convention used for AZ1, AZ4, AZ11, AZ12 in this repo.","Vdrop=24 V is read from the single-plate I/V characteristic (Philips AZ50 datasheet page A, Ia vs Va, 0–600 mA / 0–80 V) at 150 mA per plate (= Idc_max 300 mA / 2 for full-wave). The datasheet does not state a discrete Vdrop value.","The CV1264 (GEC/Mullard) and FW4/500 are listed by Radiomuseum.org as 'normally replaceable — slightly different' for the AZ50. Both use the same B4 base but draw 3.4 A filament current vs the AZ50's 3 A — they will stress a heater supply designed for 3 A and should not be treated as drop-in replacements without verifying the heater supply rating.","The RGN4004 (Telefunken/Siemens) appears on the same B4 base with a 4 A filament — it is a higher-rated variant, not pin-compatible in circuits designed for the AZ50's 3 A heater."],"references":["https://frank.pocnet.net/sheets/030/a/AZ50.pdf"],"source_urls":{"r_type":null,"tdsl":"https://tdsl.duncanamps.com/show.php?des=AZ50","radiomuseum":"https://www.radiomuseum.org/tubes/tube_az50.html"},"raw_equivalents":[],"equivalents":[],"similar":[{"type_number":"AZ4","reason":"Electrically related Philips high-current rectifier but uses P8A 8-pin side-contact base — different socket, not pin-compatible","has_detail_page":true},{"type_number":"CV1264","reason":"B4 base, 4V heater but 3.4 A filament (vs AZ50's 3 A) — draws more heater current, not a safe drop-in in circuits with fused 3 A heater supply","has_detail_page":false},{"type_number":"RGN4004","reason":"B4 base, same function, but 4 A filament (vs AZ50's 3 A) — Telefunken/Siemens designation for a higher-rated variant; incompatible heater transformer winding","has_detail_page":false}],"pins":[{"pin_number":"1","function":"Anode 1 (Plate 1)","function_code":"a1","notes":null},{"pin_number":"2","function":"Filament","function_code":"f","notes":null},{"pin_number":"3","function":"Filament","function_code":"f","notes":null},{"pin_number":"4","function":"Anode 2 (Plate 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":"3","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":"500","numeric_value":"500","unit":"V","param_group":"absolute_max"},{"key":"PIV","display_name":"Peak Inverse Voltage","value":"1414","numeric_value":"1414","unit":"V","param_group":"rectifier"},{"key":"Vdrop","display_name":"Voltage Drop (typical)","value":"24","numeric_value":"24","unit":"V","param_group":"rectifier"},{"key":"C_max","display_name":"Max C-input Filter Capacitor","value":"64","numeric_value":"64","unit":"µF","param_group":"rectifier"},{"key":"Idc_max","display_name":"Max DC Output Current (total, not per-anode)","value":"300","numeric_value":"300","unit":"mA","param_group":"rectifier"},{"key":"Rs_min","display_name":"Min Series Resistance (C-input)","value":"100","numeric_value":"100","unit":"Ω","param_group":"rectifier"}]}],"synced_at":"2026-04-21T23:11:59.684Z"}