{"type_number":"EF92","canonical_url":"https://tubeofile.com/tubes/EF92","manufacturer":"Mullard","tube_type_key":"ss_pentode","tube_type_display_name":"Small Signal Pentode","base_name":"B7G","description":"Indirectly heated variable-mu RF/IF pentode in miniature B7G envelope. Widely used in British communications and test equipment. The CV131 military designation covers this type.","is_directly_heated":false,"completeness":"medium","notes":["Variable-mu pentode suitable for AGC-controlled RF/IF amplifier stages.","Very low grid-anode capacitance (0.004 pF) permits stable operation at high frequencies without neutralisation.","Calculated amplification factor mu = gm x ra = 2.5 x 1000 = 2500."],"references":["https://frank.pocnet.net/sheets/050/e/EF92.pdf"],"source_urls":{"r_type":null,"tdsl":"https://tdsl.duncanamps.com/show.php?des=EF92","radiomuseum":"https://www.radiomuseum.org/tubes/tube_ef92.html"},"raw_equivalents":["6CQ6","W77","CV131","6F21","9D6"],"equivalents":[],"similar":[{"type_number":"6065","reason":"Slightly different variant","has_detail_page":true},{"type_number":"CV4015","reason":"Military premium-grade version","has_detail_page":true},{"type_number":"M8161","reason":"Higher quality grade of the same design","has_detail_page":true}],"pins":[{"pin_number":"1","function":"Anode (Plate)","function_code":"a","notes":null},{"pin_number":"2","function":"Screen Grid (g2)","function_code":"g2","notes":null},{"pin_number":"3","function":"Heater","function_code":"h","notes":null},{"pin_number":"4","function":"Heater","function_code":"h","notes":null},{"pin_number":"5","function":"Suppressor Grid (g3)","function_code":"g3","notes":null},{"pin_number":"6","function":"Cathode","function_code":"k","notes":null},{"pin_number":"7","function":"Control Grid (g1)","function_code":"g1","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":"Pentode","tube_type_key":"ss_pentode","specs":[{"key":"Va","display_name":"Anode Voltage (typical)","value":"250","numeric_value":"250","unit":"V","param_group":"typical_operating"},{"key":"Vs","display_name":"Screen Voltage (typical)","value":"200","numeric_value":"200","unit":"V","param_group":"typical_operating"},{"key":"Vg","display_name":"Grid 1 Bias Voltage","value":"-2.5","numeric_value":"-2.5","unit":"V","param_group":"typical_operating"},{"key":"mAa","display_name":"Anode Current","value":"8.0","numeric_value":"8","unit":"mA","param_group":"typical_operating"},{"key":"mAs","display_name":"Screen Current","value":"2.1","numeric_value":"2.1","unit":"mA","param_group":"typical_operating"},{"key":"ra","display_name":"Anode Resistance","value":"1000000","numeric_value":"1000000","unit":"Ω","param_group":"typical_operating"},{"key":"gm","display_name":"Transconductance","value":"2.5","numeric_value":"2.5","unit":"mA/V","param_group":"typical_operating"},{"key":"Cgp","display_name":"Grid-to-Plate Capacitance","value":"0.004","numeric_value":"0.004","unit":"pF","param_group":"capacitances"},{"key":"Cgk","display_name":"Grid-to-Cathode Capacitance","value":"4.5","numeric_value":"4.5","unit":"pF","param_group":"capacitances"},{"key":"Cak","display_name":"Anode-to-Cathode Capacitance","value":"7.0","numeric_value":"7","unit":"pF","param_group":"capacitances"}]}],"synced_at":"2026-04-07T12:42:19.569Z"}