{"type_number":"5R4","canonical_url":"https://tubeofile.com/tubes/5R4","manufacturer":null,"tube_type_key":"rectifier","tube_type_display_name":"Rectifier","base_name":"Octal","description":"Full-wave vacuum rectifier designed for high-voltage power supply applications. Directly heated (filament cathode). Contains two diodes with a common filament in a full-wave center-tapped configuration. Notable for exceptionally high peak inverse voltage rating (2800 V) among 5 V rectifiers, making it suitable for transmitter and high-voltage audio equipment.","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.","PIV rating is current-dependent: 2800 V at 150 mA, 2400 V at 175 mA, 2100 V at 250 mA. Design must respect both PIV and current limits simultaneously.","Relatively high voltage drop (~67 V at 250 mA) compared to indirectly-heated rectifiers like 5AR4/GZ34. This limits usable output voltage but provides natural soft-start characteristics.","Maximum first filter capacitor is only 4 µF with a minimum series resistance of 250 Ω for capacitor-input filter. The 5R4GYB relaxes this to 20 µF.","The G suffix denotes glass envelope, Y denotes micanol base. 5R4GYA is the ruggedized version; 5R4GYB has higher voltage rating (900 V RMS per plate, 3000 V PIV).","Pins 4 and 6 are the two anodes (plates) for full-wave center-tapped rectification. Pins 1, 3, 5, 7 have no connection — spacing provides high-voltage insulation between plate pins and filament pins."],"references":["https://frank.pocnet.net/sheets/049/5/5R4GY.pdf","https://frank.pocnet.net/sheets/049/5/5R4GYB.pdf"],"source_urls":{"r_type":"http://www.r-type.org/exhib/aaa0145.htm","tdsl":"http://tdsl.duncanamps.com/show.php?des=5R4","radiomuseum":"https://www.radiomuseum.org/tubes/tube_5r4.html"},"raw_equivalents":["5R4G","5R4GY","5R4GYA","5R4GYB","CV717","5R4GA","5R4GB","5R4WGY"],"equivalents":[],"similar":[{"type_number":"274B","reason":"Electrically similar but 4-pin UX4 base vs Octal for 5R4","has_detail_page":false},{"type_number":"5931","reason":"Same Octal pinout (base 5T) but draws 3.0A filament vs 2.0A for 5R4, and lower Vdrop (47V vs 67V). Industrial-grade 5U4 variant.","has_detail_page":false},{"type_number":"5U4G","reason":"Same Octal pinout (base 5T) but draws 3.0A filament vs 2.0A for 5R4, and lower PIV (1550V vs 2800V). Heater supply must handle the current difference.","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":"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":"750","numeric_value":"750","unit":"V","param_group":"absolute_max"},{"key":"PIV","display_name":"Peak Inverse Voltage","value":"2800","numeric_value":"2800","unit":"V","param_group":"rectifier"},{"key":"Vdrop","display_name":"Voltage Drop (typical)","value":"67","numeric_value":"67","unit":"V","param_group":"rectifier"},{"key":"C_max","display_name":"Max C-input Filter Capacitor","value":"4","numeric_value":"4","unit":"µF","param_group":"rectifier"},{"key":"Idc_max","display_name":"Max DC Output Current (total, not per-anode)","value":"250","numeric_value":"250","unit":"mA","param_group":"rectifier"},{"key":"Rs_min","display_name":"Min Series Resistance (C-input)","value":"250","numeric_value":"250","unit":"Ω","param_group":"rectifier"}]}],"synced_at":"2026-04-08T07:50:31.998Z"}