{"type_number":"416D","canonical_url":"https://tubeofile.com/tubes/416D","manufacturer":"Western Electric","tube_type_key":"power_triode","tube_type_display_name":"Power Triode","base_name":"DiscSeal4","description":"Western Electric disc-seal planar triode designed for microwave amplifier and oscillator service at frequencies above 3 GHz. Gold-plated body with ceramic (BeO) spacers. Top pin connects to the anode, a threaded ring provides the grid connection, and a four-pin base carries the heater and cathode. Selected for 5 watts output power at 4 GHz. Successor to the 416C with improved performance and reliability.","is_directly_heated":false,"completeness":"high","notes":["Disc-seal (lighthouse) construction with planar electrode geometry minimizes lead inductance for SHF/EHF operation.","Gold-plated body provides low-loss RF grounding contact. Early versions used glass spacers; later production switched to beryllium oxide (BeO) ceramic for better thermal conductivity.","Anode connection via top pin; grid via threaded ring on the body; cathode and heater via the four-pin base.","Requires a coaxial cavity or waveguide mounting structure for microwave operation — not usable in conventional sockets.","Handle with care: BeO ceramic is hazardous if fractured or ground to dust. Do not break or machine the ceramic spacers.","Predecessor tube 416C; the 416D is a selected version with tighter parameter tolerances for higher-frequency operation."],"references":["https://tdsl.duncanamps.com/show.php?des=416D","https://www.radiomuseum.org/tubes/?tube=416D"],"source_urls":{"r_type":null,"tdsl":"https://tdsl.duncanamps.com/show.php?des=416D","radiomuseum":"https://www.radiomuseum.org/tubes/tube_416d.html"},"raw_equivalents":[],"equivalents":[],"similar":[{"type_number":"416B","reason":"Earlier version in the 416 series — same disc-seal construction but lower ratings","has_detail_page":false},{"type_number":"416C","reason":"Direct predecessor with same physical format but lower performance specifications","has_detail_page":false}],"pins":[{"pin_number":"1","function":"Heater","function_code":"h","notes":null},{"pin_number":"2","function":"Cathode","function_code":"k","notes":null},{"pin_number":"3","function":"Heater","function_code":"h","notes":null},{"pin_number":"4","function":"Cathode","function_code":"k","notes":null},{"pin_number":"Ring","function":"Grid (Threaded Ring)","function_code":"g1","notes":null},{"pin_number":"TC","function":"Anode (Top Pin)","function_code":"a","notes":null}],"specs":[{"key":"Vh","display_name":"Heater Voltage","value":"6.3","numeric_value":"6.3","unit":"V","param_group":"heater"},{"key":"Ah","display_name":"Heater Current","value":"1.18","numeric_value":"1.18","unit":"A","param_group":"heater"}],"sections":[{"section_number":1,"section_label":"Triode","tube_type_key":"power_triode","specs":[{"key":"Va_max","display_name":"Anode Voltage (max)","value":"400","numeric_value":"400","unit":"V","param_group":"absolute_max"},{"key":"Pa_max","display_name":"Anode Dissipation (max)","value":"12","numeric_value":"12","unit":"W","param_group":"absolute_max"},{"key":"Va","display_name":"Anode Voltage (typical)","value":"250","numeric_value":"250","unit":"V","param_group":"typical_operating"},{"key":"mAa","display_name":"Anode Current","value":"50","numeric_value":"50","unit":"mA","param_group":"typical_operating"},{"key":"ra","display_name":"Anode Resistance","value":"3850","numeric_value":"3850","unit":"Ω","param_group":"typical_operating"},{"key":"gm","display_name":"Transconductance","value":"65","numeric_value":"65","unit":"mA/V","param_group":"typical_operating"},{"key":"mu","display_name":"Amplification Factor (μ)","value":"250","numeric_value":"250","unit":"—","param_group":"typical_operating"},{"key":"Pout","display_name":"Output Power","value":"5","numeric_value":"5","unit":"W","param_group":"output"},{"key":"Cgp","display_name":"Grid-to-Plate Capacitance","value":"0.035","numeric_value":"0.035","unit":"pF","param_group":"capacitances"},{"key":"Cin","display_name":"Input Capacitance","value":"2.7","numeric_value":"2.7","unit":"pF","param_group":"capacitances"},{"key":"Cout","display_name":"Output Capacitance","value":"0.6","numeric_value":"0.6","unit":"pF","param_group":"capacitances"},{"key":"freq","display_name":"Max Operating Frequency","value":"4000","numeric_value":"4000","unit":"MHz","param_group":"noise_rf"}]}],"synced_at":"2026-04-07T12:09:39.692Z"}