{"type_number":"PL36","canonical_url":"https://tubeofile.com/tubes/PL36","manufacturer":"Philips","tube_type_key":"power_pentode","tube_type_display_name":"Power Pentode","base_name":"Octal","description":"Output pentode designed for use as a line output tube in television receivers; 300mA series-string heater variant of the EL36. Electrically identical to the EL36 except for heater specification (25V/0.3A).","is_directly_heated":false,"completeness":"high","notes":["300mA series-string heater (25V/0.3A) for AC/DC TV receivers. The 'P' prefix in Mullard/Philips nomenclature denotes a 300mA heater string design.","Valve Equivalents database confirms I/O base (Octal with top cap), 25V heater (via 25E5 entry).","Philips interchange lists 25E5 as the American equivalent designation.","Brans Vademecum lists PL81 as equivalent — this is a similar line-output pentode but with different electrical characteristics (EL81-based vs EL36-based).","Electrically identical to EL36 in all electrode characteristics; only the heater differs.","Not interchangeable with EL36/6CM5 without heater circuit modification."],"references":["https://tdsl.duncanamps.com/show.php?des=PL36","https://www.radiomuseum.org/tubes/?tube=PL36"],"source_urls":{"r_type":null,"tdsl":"https://tdsl.duncanamps.com/show.php?des=PL36","radiomuseum":"https://www.radiomuseum.org/tubes/tube_pl36.html"},"raw_equivalents":["25E5"],"equivalents":[{"type_number":"25E5","equivalence_type":"direct","notes":null}],"similar":[{"type_number":"6CM5","reason":"American designation for EL36 — same electrical characteristics but 6.3V heater","has_detail_page":false},{"type_number":"EL36","reason":"Same electrical characteristics but 6.3V/1.25A parallel heater — not a drop-in in 300mA series-string circuits","has_detail_page":true},{"type_number":"PL81","reason":"Listed as equivalent in Brans — similar line-output pentode but different electrical characteristics","has_detail_page":true}],"pins":[{"pin_number":"1","function":"Internal Connection","function_code":"ia","notes":null},{"pin_number":"2","function":"Internal Connection (Cathode/Suppressor)","function_code":"ia","notes":null},{"pin_number":"3","function":"Heater","function_code":"h","notes":null},{"pin_number":"4","function":"Internal Connection (Cathode/Suppressor)","function_code":"ia","notes":null},{"pin_number":"5","function":"Screen Grid (g2)","function_code":"g2","notes":null},{"pin_number":"6","function":"Control Grid (g1)","function_code":"g1","notes":null},{"pin_number":"7","function":"No Connection","function_code":"nc","notes":null},{"pin_number":"8","function":"Heater","function_code":"h","notes":null},{"pin_number":"TC","function":"Anode (Top Cap)","function_code":"a","notes":null}],"specs":[{"key":"Vh","display_name":"Heater Voltage","value":"25","numeric_value":"25","unit":"V","param_group":"heater"},{"key":"Ah","display_name":"Heater Current","value":"0.3","numeric_value":"0.3","unit":"A","param_group":"heater"}],"sections":[{"section_number":1,"section_label":"Pentode","tube_type_key":"power_pentode","specs":[{"key":"Va_max","display_name":"Anode Voltage (max)","value":"250","numeric_value":"250","unit":"V","param_group":"absolute_max"},{"key":"Vs_max","display_name":"Screen Voltage (max)","value":"250","numeric_value":"250","unit":"V","param_group":"absolute_max"},{"key":"Pa_max","display_name":"Anode Dissipation (max)","value":"12","numeric_value":"12","unit":"W","param_group":"absolute_max"},{"key":"Ps_max","display_name":"Screen Dissipation (max)","value":"5","numeric_value":"5","unit":"W","param_group":"absolute_max"},{"key":"Ik_max","display_name":"Cathode Current (max)","value":"200","numeric_value":"200","unit":"mA","param_group":"absolute_max"},{"key":"Vhk_max","display_name":"Heater-to-Cathode Voltage (max)","value":"100","numeric_value":"100","unit":"V","param_group":"absolute_max"},{"key":"Rg_max","display_name":"Max Grid Resistor","value":"0.5","numeric_value":"0.5","unit":"MΩ","param_group":"absolute_max"},{"key":"Va","display_name":"Anode Voltage (typical)","value":"100","numeric_value":"100","unit":"V","param_group":"typical_operating"},{"key":"Vs","display_name":"Screen Voltage (typical)","value":"100","numeric_value":"100","unit":"V","param_group":"typical_operating"},{"key":"Vg","display_name":"Grid 1 Bias Voltage","value":"-8.2","numeric_value":"-8.2","unit":"V","param_group":"typical_operating"},{"key":"mAa","display_name":"Anode Current","value":"100","numeric_value":"100","unit":"mA","param_group":"typical_operating"},{"key":"mAs","display_name":"Screen Current","value":"7","numeric_value":"7","unit":"mA","param_group":"typical_operating"},{"key":"ra","display_name":"Anode Resistance","value":"5000","numeric_value":"5000","unit":"Ω","param_group":"typical_operating"},{"key":"gm","display_name":"Transconductance","value":"14","numeric_value":"14","unit":"mA/V","param_group":"typical_operating"},{"key":"Pout","display_name":"Output Power","value":"44.5","numeric_value":"44.5","unit":"W","param_group":"output"},{"key":"rl","display_name":"Load Impedance","value":"3500","numeric_value":"3500","unit":"Ω","param_group":"output"},{"key":"Cgp","display_name":"Grid-to-Plate Capacitance","value":"1.1","numeric_value":"1.1","unit":"pF","param_group":"capacitances"},{"key":"Cgk","display_name":"Grid-to-Cathode Capacitance","value":"17.5","numeric_value":"17.5","unit":"pF","param_group":"capacitances"},{"key":"Cak","display_name":"Anode-to-Cathode Capacitance","value":"8","numeric_value":"8","unit":"pF","param_group":"capacitances"}]},{"section_number":2,"section_label":"Triode Strapped","tube_type_key":"power_triode","specs":[{"key":"Va_max","display_name":"Anode Voltage (max)","value":"250","numeric_value":"250","unit":"V","param_group":"absolute_max"},{"key":"Pa_max","display_name":"Anode Dissipation (max)","value":"13","numeric_value":"13","unit":"W","param_group":"absolute_max"},{"key":"Ik_max","display_name":"Cathode Current (max)","value":"200","numeric_value":"200","unit":"mA","param_group":"absolute_max"},{"key":"Va","display_name":"Anode Voltage (typical)","value":"375","numeric_value":"375","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":"800","numeric_value":"800","unit":"Ω","param_group":"typical_operating"},{"key":"gm","display_name":"Transconductance","value":"6.8","numeric_value":"6.8","unit":"mA/V","param_group":"typical_operating"},{"key":"mu","display_name":"Amplification Factor (μ)","value":"5","numeric_value":"5","unit":"—","param_group":"typical_operating"},{"key":"Pout","display_name":"Output Power","value":"7.8","numeric_value":"7.8","unit":"W","param_group":"output"},{"key":"rl","display_name":"Load Impedance","value":"6400","numeric_value":"6400","unit":"Ω","param_group":"output"}]}],"synced_at":"2026-04-07T12:50:30.763Z"}