{"type_number":"12J5GT","canonical_url":"https://tubeofile.com/tubes/12J5GT","manufacturer":null,"tube_type_key":"small_signal_triode","tube_type_display_name":"Small Signal Triode","base_name":"Octal","description":"Medium-mu general purpose triode designed for use in resistance coupled amplifiers, super-heterodyne circuits as an oscillator, or as a detector. Electrically identical to the 6J5GT except for heater voltage. High mutual conductance and low output capacitance make it especially suited for high frequency oscillator service.","is_directly_heated":false,"completeness":"high","notes":["Electrically identical to the 6J5/6J5GT except for heater voltage (12.6V vs 6.3V).","Heater-cathode voltage should be kept to a minimum if direct connection is not possible (GE datasheet). Max Vhk = 90V DC.","Pin 1 (shell) should be connected to cathode per GE datasheet.","The d-c resistance in the grid circuit under maximum rated conditions should not exceed 1.0 megohm."],"references":["https://frank.pocnet.net/sheets/201/1/12J5GT.pdf","https://frank.pocnet.net/sheets/201/1/12J5.pdf"],"source_urls":{"r_type":"http://www.r-type.org/exhib/abh0099.htm","tdsl":"https://tdsl.duncanamps.com/show.php?des=12J5GT","radiomuseum":"https://www.radiomuseum.org/tubes/tube_12j5gt.html"},"raw_equivalents":["12J5","CV534","CV535","VT135","VT135A","12J5WGT","6J5"],"equivalents":[{"type_number":"12J5","equivalence_type":"direct","notes":null},{"type_number":"6J5","equivalence_type":"direct","notes":null}],"similar":[],"pins":[{"pin_number":"1","function":"Shell","function_code":"ia","notes":null},{"pin_number":"2","function":"Heater","function_code":"h","notes":null},{"pin_number":"3","function":"Plate","function_code":"a","notes":null},{"pin_number":"4","function":"No Connection","function_code":"nc","notes":null},{"pin_number":"5","function":"Grid","function_code":"g1","notes":null},{"pin_number":"6","function":"No Connection","function_code":"nc","notes":null},{"pin_number":"7","function":"Heater","function_code":"h","notes":null},{"pin_number":"8","function":"Cathode","function_code":"k","notes":null}],"specs":[{"key":"Vh","display_name":"Heater Voltage","value":"12.6","numeric_value":"12.6","unit":"V","param_group":"heater"},{"key":"Ah","display_name":"Heater Current","value":"0.15","numeric_value":"0.15","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":"300","numeric_value":"300","unit":"V","param_group":"absolute_max"},{"key":"Pa_max","display_name":"Anode Dissipation (max)","value":"2.5","numeric_value":"2.5","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":"90","numeric_value":"90","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":"9.0","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":"2600","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":"3.4","numeric_value":"3.4","unit":"pF","param_group":"capacitances"},{"key":"Cin","display_name":"Input Capacitance","value":"3.4","numeric_value":"3.4","unit":"pF","param_group":"capacitances"},{"key":"Cout","display_name":"Output Capacitance","value":"3.6","numeric_value":"3.6","unit":"pF","param_group":"capacitances"}]}],"synced_at":"2026-04-07T19:00:48.194Z"}