{"type_number":"3C24","canonical_url":"https://tubeofile.com/tubes/3C24","manufacturer":"Heintz & Kaufman","tube_type_key":"power_triode","tube_type_display_name":"Power Triode","base_name":"UX4","description":"Directly heated VHF transmitting triode developed by Heintz & Kaufman (Gammatron). Uses a UX4 base with side contact for the grid and top cap for the anode. Designed for RF oscillator and amplifier service at frequencies up to VHF. Rated at 25 watts plate dissipation. Originally designated 24G or 24-G Gammatron.","is_directly_heated":true,"completeness":"high","notes":["Grid connection is via a side contact on the envelope, not through the base pins. Anode connects through a top cap.","Originally designated 24-G Gammatron by Heintz & Kaufman; RETMA assigned the 3C24 type number.","VT-204 is the US military designation for this tube.","Thoriated tungsten filament requires careful reactivation procedure if overloaded.","Suitable for RF oscillator, amplifier, and modulator service in VHF equipment."],"references":["https://frank.yueksel.org/sheets/030/3/3C24.pdf"],"source_urls":{"r_type":null,"tdsl":"https://tdsl.duncanamps.com/show.php?des=3C24","radiomuseum":"https://www.radiomuseum.org/tubes/tube_3c24.html"},"raw_equivalents":["VT-204","HK24G","24G","CV2736","CV789"],"equivalents":[],"similar":[{"type_number":"3C28","reason":"Related Gammatron transmitting triode listed alongside 3C24 on TDSL — different power rating","has_detail_page":false}],"pins":[{"pin_number":"1","function":"Filament","function_code":"h","notes":null},{"pin_number":"2","function":"No Connection","function_code":"nc","notes":null},{"pin_number":"3","function":"No Connection","function_code":"nc","notes":null},{"pin_number":"4","function":"Filament","function_code":"h","notes":null},{"pin_number":"SC","function":"Grid (Side Contact)","function_code":"g1","notes":null},{"pin_number":"TC","function":"Anode (Top Cap)","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":"3.0","numeric_value":"3","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":"1500","numeric_value":"1500","unit":"V","param_group":"absolute_max"},{"key":"Pa_max","display_name":"Anode Dissipation (max)","value":"25","numeric_value":"25","unit":"W","param_group":"absolute_max"},{"key":"Va","display_name":"Anode Voltage (typical)","value":"1000","numeric_value":"1000","unit":"V","param_group":"typical_operating"},{"key":"Vg","display_name":"Grid 1 Bias Voltage","value":"-60","numeric_value":"-60","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":"6700","numeric_value":"6700","unit":"Ω","param_group":"typical_operating"},{"key":"gm","display_name":"Transconductance","value":"3.0","numeric_value":"3","unit":"mA/V","param_group":"typical_operating"},{"key":"mu","display_name":"Amplification Factor (μ)","value":"20","numeric_value":"20","unit":"—","param_group":"typical_operating"},{"key":"Cgp","display_name":"Grid-to-Plate Capacitance","value":"2.2","numeric_value":"2.2","unit":"pF","param_group":"capacitances"},{"key":"Cin","display_name":"Input Capacitance","value":"2.5","numeric_value":"2.5","unit":"pF","param_group":"capacitances"},{"key":"Cout","display_name":"Output Capacitance","value":"1.2","numeric_value":"1.2","unit":"pF","param_group":"capacitances"},{"key":"freq","display_name":"Max Operating Frequency","value":"200","numeric_value":"200","unit":"MHz","param_group":"noise_rf"}]}],"synced_at":"2026-04-07T12:09:27.976Z"}