{"type_number":"EL42","canonical_url":"https://tubeofile.com/tubes/EL42","manufacturer":"Philips","tube_type_key":"power_pentode","tube_type_display_name":"Power Pentode","base_name":"Rimlock","description":"Low-consumption output pentode designed for car radios and equipment where low power consumption is critical. Indirectly heated with only 200 mA heater current (1.26 W). Delivers 2.8 W in Class A single-ended or 7 W in Class A push-pull.","is_directly_heated":false,"completeness":"high","notes":["Pins 3 and 4 are internal connections (not brought out to the socket). The suppressor grid is internally connected to the cathode.","Designed primarily for 6 V car radio and vibrator-driven sets. The datasheet recommends designing the operating point for 7 V supply (6 W average Pa) to tolerate accumulator voltage fluctuations between 5.5 V and 8 V without risk of under-running or overloading.","Maximum permissible anode dissipation may be exceeded by up to 15% as a result of component tolerances and AGC action.","Screen dissipation has two separate limits: max 1 W without input signal (idle) and max 2 W at maximum output power.","The EL42 was introduced by Philips in 1947 and was widely used in European car radios and portable receivers through the 1950s. It replaced the earlier EL2 and EL32, and was itself superseded by the Noval-based EL85 and EL95."],"references":["https://frank.pocnet.net/sheets/046/e/EL42.pdf"],"source_urls":{"r_type":"https://www.r-type.org/exhib/aaa0946.htm","tdsl":"https://tdsl.duncanamps.com/show.php?des=EL42","radiomuseum":"https://www.radiomuseum.org/tubes/tube_el42.html"},"raw_equivalents":["BF62","CV3890","N151"],"equivalents":[],"similar":[{"type_number":"6BN5","reason":"American designation for EL85; Noval (B9A) base — not pin-compatible with Rimlock (B8A)","has_detail_page":false},{"type_number":"EL41","reason":"Same Rimlock B8A base but different internal connections on pins 3/4 and significantly higher power (9 W Pa_max vs 6 W); not a drop-in replacement","has_detail_page":true},{"type_number":"EL85","reason":"Electrically identical but Noval (B9A) base — not pin-compatible with Rimlock (B8A)","has_detail_page":true}],"pins":[{"pin_number":"1","function":"Heater","function_code":"h","notes":null},{"pin_number":"2","function":"Anode","function_code":"a","notes":null},{"pin_number":"3","function":"Internal Connection","function_code":"ia","notes":null},{"pin_number":"4","function":"Internal Connection","function_code":"ia","notes":null},{"pin_number":"5","function":"Screen Grid","function_code":"g2","notes":null},{"pin_number":"6","function":"Control Grid","function_code":"g1","notes":null},{"pin_number":"7","function":"Cathode / Suppressor Grid (internal; g3 tied to cathode)","function_code":"k","notes":null},{"pin_number":"8","function":"Heater","function_code":"h","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":"power_pentode","specs":[{"key":"Va_max","display_name":"Anode Voltage (max)","value":"300","numeric_value":"300","unit":"V","param_group":"absolute_max"},{"key":"Vs_max","display_name":"Screen Voltage (max)","value":"300","numeric_value":"300","unit":"V","param_group":"absolute_max"},{"key":"Pa_max","display_name":"Anode Dissipation (max)","value":"6","numeric_value":"6","unit":"W","param_group":"absolute_max"},{"key":"Ps_max","display_name":"Screen Dissipation (max)","value":"2","numeric_value":"2","unit":"W","param_group":"absolute_max"},{"key":"Ik_max","display_name":"Cathode Current (max)","value":"35","numeric_value":"35","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":"2","numeric_value":"2","unit":"MΩ","param_group":"absolute_max"},{"key":"Va","display_name":"Anode Voltage (typical)","value":"225","numeric_value":"225","unit":"V","param_group":"typical_operating"},{"key":"Vs","display_name":"Screen Voltage (typical)","value":"225","numeric_value":"225","unit":"V","param_group":"typical_operating"},{"key":"Vg","display_name":"Grid 1 Bias Voltage","value":"-10","numeric_value":"-10","unit":"V","param_group":"typical_operating"},{"key":"mAa","display_name":"Anode Current","value":"26","numeric_value":"26","unit":"mA","param_group":"typical_operating"},{"key":"mAs","display_name":"Screen Current","value":"4.1","numeric_value":"4.1","unit":"mA","param_group":"typical_operating"},{"key":"ra","display_name":"Anode Resistance","value":"90000","numeric_value":"90000","unit":"Ω","param_group":"typical_operating"},{"key":"gm","display_name":"Transconductance","value":"3.2","numeric_value":"3.2","unit":"mA/V","param_group":"typical_operating"},{"key":"Rk","display_name":"Cathode Resistor (self-bias)","value":"360","numeric_value":"360","unit":"Ω","param_group":"typical_operating"},{"key":"Pout","display_name":"Output Power","value":"2.8","numeric_value":"2.8","unit":"W","param_group":"output"},{"key":"rl","display_name":"Load Impedance","value":"9000","numeric_value":"9000","unit":"Ω","param_group":"output"},{"key":"Cgp","display_name":"Grid-to-Plate Capacitance","value":"<0.2","numeric_value":null,"unit":"pF","param_group":"capacitances"},{"key":"Cin","display_name":"Input Capacitance","value":"4.3","numeric_value":"4.3","unit":"pF","param_group":"capacitances"},{"key":"Cout","display_name":"Output Capacitance","value":"6.2","numeric_value":"6.2","unit":"pF","param_group":"capacitances"},{"key":null,"display_name":"Cg1f","value":"<0.2","numeric_value":null,"unit":"pF","param_group":null},{"key":null,"display_name":"μg2g1","value":"11","numeric_value":"11","unit":"—","param_group":null},{"key":null,"display_name":"Rfk","value":"20000","numeric_value":"20000","unit":"Ω","param_group":null}]}],"synced_at":"2026-04-07T12:45:13.642Z"}