{"type_number":"8CG7","canonical_url":"https://tubeofile.com/tubes/8CG7","manufacturer":null,"tube_type_key":"small_signal_triode","tube_type_display_name":"Small Signal Triode","base_name":"Noval","description":"General-purpose medium-mu twin triode; 8.4V heater variant of the 6CG7 for series-string television receivers. Electrically identical to the 6CG7 except for heater voltage (8.4V at 0.45A instead of 6.3V at 0.6A).","is_directly_heated":false,"completeness":"high","notes":["8.4V / 0.45A heater for series-string TV receiver heater chains. Electrically identical to 6CG7/6FQ7 in all other respects.","GE Essential Characteristics confirms: medium-mu twin triode, 9AJ base (Noval), 8.4V/0.45A heater, Pa_max 3.5W, Va_max 300V, mu=20, gm=2600 umhos, ra=7700 ohms at Va=250V Vg=-8V.","8FQ7 is the same tube registered under a different JEDEC number (same relationship as 6CG7/6FQ7).","Not interchangeable with 6CG7/6FQ7 without heater circuit modification."],"references":["https://tdsl.duncanamps.com/show.php?des=8CG7","https://www.radiomuseum.org/tubes/?tube=8CG7"],"source_urls":{"r_type":null,"tdsl":"https://tdsl.duncanamps.com/show.php?des=8CG7","radiomuseum":"https://www.radiomuseum.org/tubes/tube_8cg7.html"},"raw_equivalents":["8FQ7"],"equivalents":[{"type_number":"8FQ7","equivalence_type":"direct","notes":null}],"similar":[{"type_number":"12CG7","reason":"12.6V heater version — not a drop-in in 8.4V circuits","has_detail_page":true},{"type_number":"6CG7","reason":"Same electrical characteristics but 6.3V heater — not a drop-in in 8.4V series-string circuits","has_detail_page":true},{"type_number":"6FQ7","reason":"Same tube as 6CG7 (different JEDEC number) — 6.3V heater","has_detail_page":false},{"type_number":"6SN7GT","reason":"Electrically near-identical but Octal base — not pin-compatible","has_detail_page":false}],"pins":[{"pin_number":"1","function":"Plate (Section 2)","function_code":"a2","notes":null},{"pin_number":"2","function":"Grid (Section 2)","function_code":"g1_2","notes":null},{"pin_number":"3","function":"Cathode (Section 2)","function_code":"k2","notes":null},{"pin_number":"4","function":"Heater","function_code":"h","notes":null},{"pin_number":"5","function":"Heater","function_code":"h","notes":null},{"pin_number":"6","function":"Plate (Section 1)","function_code":"a1","notes":null},{"pin_number":"7","function":"Grid (Section 1)","function_code":"g1_1","notes":null},{"pin_number":"8","function":"Cathode (Section 1)","function_code":"k1","notes":null},{"pin_number":"9","function":"Internal Shield","function_code":"ia","notes":null}],"specs":[{"key":"Vh","display_name":"Heater Voltage","value":"8.4","numeric_value":"8.4","unit":"V","param_group":"heater"},{"key":"Ah","display_name":"Heater Current","value":"0.45","numeric_value":"0.45","unit":"A","param_group":"heater"}],"sections":[{"section_number":1,"section_label":"Triode (each section)","tube_type_key":"small_signal_triode","specs":[{"key":"Va_max","display_name":"Anode Voltage (max)","value":"300","numeric_value":"300","unit":"V","param_group":"absolute_max"},{"key":"Pa_max","display_name":"Anode Dissipation (max)","value":"3.5","numeric_value":"3.5","unit":"W","param_group":"absolute_max"},{"key":"Ik_max","display_name":"Cathode Current (max)","value":"20","numeric_value":"20","unit":"mA","param_group":"absolute_max"},{"key":"Vhk_max","display_name":"Heater-to-Cathode Voltage (max)","value":"200","numeric_value":"200","unit":"V","param_group":"absolute_max"},{"key":"Rg_max","display_name":"Max Grid Resistor","value":"1.0","numeric_value":"1","unit":"MΩ","param_group":"absolute_max"},{"key":"Va","display_name":"Anode Voltage (typical)","value":"250","numeric_value":"250","unit":"V","param_group":"typical_operating"},{"key":"Vg","display_name":"Grid 1 Bias Voltage","value":"-8","numeric_value":"-8","unit":"V","param_group":"typical_operating"},{"key":"mAa","display_name":"Anode Current","value":"9","numeric_value":"9","unit":"mA","param_group":"typical_operating"},{"key":"ra","display_name":"Anode Resistance","value":"7700","numeric_value":"7700","unit":"Ω","param_group":"typical_operating"},{"key":"gm","display_name":"Transconductance","value":"2.6","numeric_value":"2.6","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":"4.0","numeric_value":"4","unit":"pF","param_group":"capacitances"},{"key":"Cin","display_name":"Input Capacitance","value":"2.3","numeric_value":"2.3","unit":"pF","param_group":"capacitances"},{"key":"Cout","display_name":"Output Capacitance","value":"2.2","numeric_value":"2.2","unit":"pF","param_group":"capacitances"}]}],"synced_at":"2026-04-07T12:34:42.096Z"}