{"type_number":"6EN4","canonical_url":"https://tubeofile.com/tubes/6EN4","manufacturer":"RCA","tube_type_key":"small_signal_triode","tube_type_display_name":"Small Signal Triode","base_name":"Octal","description":"Sharp-Cutoff Beam Triode. High-voltage, low-current type shunt voltage regulator for DC power supplies in colour-TV receivers. Designed to minimise X-radiation.","is_directly_heated":false,"completeness":"high","notes":["Plate (anode) connects via top-cap (JEDEC C1-50) — not a base pin. Use a flexible lead connector to avoid strain on the cap seal.","Pins 3, 4, and 8 are 'Do Not Use' — socket terminals for these pins must not be used as tie points or tube performance may be adversely affected.","For new equipment design, make grid connection to pin 6 only (pin 5 is a legacy connection).","Heater positive with respect to cathode is Not Recommended. Heater negative with respect to cathode: 450 V max (sufficient impedance must be in series with cathode to limit current to 450 mA under short-circuit conditions).","Operates at up to 30,000 V DC plate voltage — produces X-radiation under normal operating conditions. Equipment must provide adequate shielding. The blue glow on the inner bulb surface is fluorescence, not a gas indication.","The bulb becomes hot in operation — free air circulation must be provided around the tube.","Grid-circuit resistance maximum: 3 MΩ."],"references":["https://frank.yueksel.org/sheets/049/6/6EN4.pdf"],"source_urls":{"r_type":null,"tdsl":"https://tdsl.duncanamps.com/show.php?des=6EN4","radiomuseum":"https://www.radiomuseum.org/tubes/tube_6en4.html"},"raw_equivalents":[],"equivalents":[],"similar":[{"type_number":"6BK4C","reason":"Similar HV shunt regulator; different part number series, pin compatibility not confirmed","has_detail_page":false},{"type_number":"6EL4","reason":"Similar HV shunt regulator triode; pin compatibility not confirmed","has_detail_page":false}],"pins":[{"pin_number":"1","function":"Cathode, Internal Shield","function_code":"k","notes":null},{"pin_number":"2","function":"Heater","function_code":"h","notes":null},{"pin_number":"3","function":"Do Not Use","function_code":"nc","notes":null},{"pin_number":"4","function":"Do Not Use","function_code":"nc","notes":null},{"pin_number":"5","function":"Grid (legacy — use pin 6 for new designs)","function_code":"g1","notes":null},{"pin_number":"6","function":"Grid (preferred connection)","function_code":"g1","notes":null},{"pin_number":"7","function":"Heater","function_code":"h","notes":null},{"pin_number":"8","function":"Do Not Use","function_code":"nc","notes":null},{"pin_number":"cap","function":"Plate (top cap)","function_code":"tc","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":"0.2","numeric_value":"0.2","unit":"A","param_group":"heater"}],"sections":[{"section_number":1,"section_label":"Triode","tube_type_key":"small_signal_triode","specs":[{"key":"Va_max","display_name":"Anode Voltage (max)","value":"30000","numeric_value":"30000","unit":"V","param_group":"absolute_max"},{"key":"Pa_max","display_name":"Anode Dissipation (max)","value":"40","numeric_value":"40","unit":"W","param_group":"absolute_max"},{"key":"Ik_max","display_name":"Cathode Current (max)","value":"1.6","numeric_value":"1.6","unit":"mA","param_group":"absolute_max"},{"key":"Vhk_max","display_name":"Heater-to-Cathode Voltage (max)","value":"450","numeric_value":"450","unit":"V","param_group":"absolute_max"},{"key":"Rg_max","display_name":"Max Grid Resistor","value":"3","numeric_value":"3","unit":"MΩ","param_group":"absolute_max"},{"key":"Va","display_name":"Anode Voltage (typical)","value":"30000","numeric_value":"30000","unit":"V","param_group":"typical_operating"},{"key":"Vg","display_name":"Grid 1 Bias Voltage","value":"-7","numeric_value":"-7","unit":"V","param_group":"typical_operating"},{"key":"mAa","display_name":"Anode Current","value":"0.045","numeric_value":"0.045","unit":"mA","param_group":"typical_operating"},{"key":"ra","display_name":"Anode Resistance","value":"10000000","numeric_value":"10000000","unit":"Ω","param_group":"typical_operating"},{"key":"gm","display_name":"Transconductance","value":"0.2","numeric_value":"0.2","unit":"mA/V","param_group":"typical_operating"},{"key":"mu","display_name":"Amplification Factor (μ)","value":"2000","numeric_value":"2000","unit":"—","param_group":"typical_operating"},{"key":"Cgp","display_name":"Grid-to-Plate Capacitance","value":"1.0","numeric_value":"1","unit":"pF","param_group":"capacitances"},{"key":"Cin","display_name":"Input Capacitance","value":"2.6","numeric_value":"2.6","unit":"pF","param_group":"capacitances"},{"key":"Cout","display_name":"Output Capacitance","value":"1.0","numeric_value":"1","unit":"pF","param_group":"capacitances"}]}],"synced_at":"2026-04-07T12:22:27.692Z"}