{"type_number":"3DG4","canonical_url":"https://tubeofile.com/tubes/3DG4","manufacturer":null,"tube_type_key":"rectifier","tube_type_display_name":"Rectifier","base_name":"UX5","description":"Twin diode with directly heated cathode designed for use as a full-wave rectifier in the power supply of television receivers.","is_directly_heated":true,"completeness":"high","notes":["Base is EIA 5DE (Short Medium-Shell Octal 5-Pin) — a 5-pin variant of the International Octal base used almost exclusively in TV rectifier service. Not compatible with standard 8-pin Octal sockets.","Opposite ends of the directly heated cathode are connected to pins 1 and 3. Cathode-heating voltage should be connected between these pins. Output current may be taken from either pin 1 or pin 3.","Pin 2 is an internal connection and must not be used.","The reference table 'tube rectifiers.pdf' lists Vdrop as 32V, but both the GE and Tung-Sol datasheets specify 25V at 350 mA DC per plate. The datasheet value of 25V is used here.","Designed for Zenith and other TV sets of the early 1960s. The 3.3V/3.8A filament is unusual and limits substitution options — no other common rectifier shares this filament voltage and base."],"references":["https://frank.pocnet.net/sheets/127/3/3DG4.pdf","https://tube-data.com/sheets/093/3/3DG4.pdf"],"source_urls":{"r_type":null,"tdsl":"https://tdsl.duncanamps.com/show.php?des=3DG4","radiomuseum":"https://www.radiomuseum.org/tubes/tube_3dg4.html"},"raw_equivalents":["3DH3"],"equivalents":[],"similar":[],"pins":[{"pin_number":"1","function":"Cathode (Filament)","function_code":"k","notes":null},{"pin_number":"2","function":"Internal Connection — Do Not Use","function_code":"ia","notes":null},{"pin_number":"3","function":"Cathode (Filament)","function_code":"k","notes":null},{"pin_number":"5","function":"Plate 2","function_code":"a2","notes":null},{"pin_number":"7","function":"Plate 1","function_code":"a1","notes":null}],"specs":[{"key":"Vh","display_name":"Heater Voltage","value":"3.3","numeric_value":"3.3","unit":"V","param_group":"heater"},{"key":"Ah","display_name":"Heater Current","value":"3.8","numeric_value":"3.8","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":"375","numeric_value":"375","unit":"V","param_group":"absolute_max"},{"key":"PIV","display_name":"Peak Inverse Voltage","value":"1050","numeric_value":"1050","unit":"V","param_group":"rectifier"},{"key":"Vdrop","display_name":"Voltage Drop (typical)","value":"25","numeric_value":"25","unit":"V","param_group":"rectifier"},{"key":"C_max","display_name":"Max C-input Filter Capacitor","value":"40","numeric_value":"40","unit":"µF","param_group":"rectifier"},{"key":"Ia_peak","display_name":"Peak Anode Current (surge)","value":"1200","numeric_value":"1200","unit":"mA","param_group":"rectifier"},{"key":"Idc_max","display_name":"Max DC Output Current (total, not per-anode)","value":"350","numeric_value":"350","unit":"mA","param_group":"rectifier"},{"key":"Rs_min","display_name":"Min Series Resistance (C-input)","value":"32","numeric_value":"32","unit":"Ω","param_group":"rectifier"}]}],"synced_at":"2026-04-08T07:50:14.397Z"}