{"type_number":"1LE3","canonical_url":"https://tubeofile.com/tubes/1LE3","manufacturer":"RCA","tube_type_key":"small_signal_triode","tube_type_display_name":"Small Signal Triode","base_name":"Loctal","description":"Medium-mu triode for battery-operated equipment. Directly-heated (filament-type) coated cathode with 1.4V/0.05A filament. Lock-in 8-pin (Loctal) base, basing 4AA. Designed for Class A1 amplifier service in portable battery receivers.","is_directly_heated":true,"completeness":"medium","notes":["RCA Tube Department data, October 15, 1947. Lock-in 8-pin base (Loctal), basing designation 4AA. Glass T-9 bulb.","Directly-heated filament type. Filament voltage 1.4V DC, filament current 0.05A.","Pin 5 is internal connection — do not use. Pin 3 and Pin 4 are no connection.","Direct interelectrode capacitances (triode unit, with external shield connected to negative filament terminal): grid-to-plate 1.7 pF, grid-to-cathode 1.7 pF, plate-to-cathode 3.0 pF.","Maximum plate voltage 110V.","TDSL lists VT239 as close or identical substitute.","Two operating conditions: (1) Va=90V, Vg=0V, mu=14.5, ra=11200 ohms, gm=1300 umhos, Ia=4.5 mA; (2) Va=90V, Vg=-3V, mu=14.5, ra=19000 ohms, gm=760 umhos, Ia=1.4 mA.","NOTE: Despite user expectation of a damper/rectifier type, the RCA datasheet clearly identifies this as a MEDIUM-MU TRIODE for amplifier service."],"references":["https://frank.pocnet.net/sheets/049/1/1LE3.pdf"],"source_urls":{"r_type":null,"tdsl":"https://tdsl.duncanamps.com/show.php?des=1LE3","radiomuseum":"https://www.radiomuseum.org/tubes/tube_1LE3.html"},"raw_equivalents":["VT239"],"equivalents":[],"similar":[],"pins":[{"pin_number":"1","function":"Filament (+)","function_code":"h","notes":null},{"pin_number":"2","function":"Plate","function_code":"a","notes":null},{"pin_number":"3","function":"No Connection","function_code":"nc","notes":null},{"pin_number":"4","function":"No Connection","function_code":"nc","notes":null},{"pin_number":"5","function":"Internal Connection — Do Not Use","function_code":"ic","notes":null},{"pin_number":"6","function":"Grid","function_code":"g1","notes":null},{"pin_number":"7","function":"No Connection","function_code":"nc","notes":null},{"pin_number":"8","function":"Filament (−)","function_code":"h","notes":null}],"specs":[{"key":"Vh","display_name":"Heater Voltage","value":"1.4","numeric_value":"1.4","unit":"V","param_group":"heater"},{"key":"Ah","display_name":"Heater Current","value":"0.05","numeric_value":"0.05","unit":"A","param_group":"heater"}],"sections":[{"section_number":1,"section_label":"Triode — Class A1 Amplifier","tube_type_key":"small_signal_triode","specs":[{"key":"Va_max","display_name":"Anode Voltage (max)","value":"110","numeric_value":"110","unit":"V","param_group":"absolute_max"},{"key":"Va","display_name":"Anode Voltage (typical)","value":"90","numeric_value":"90","unit":"V","param_group":"typical_operating"},{"key":"Vg","display_name":"Grid 1 Bias Voltage","value":"0","numeric_value":"0","unit":"V","param_group":"typical_operating"},{"key":"mAa","display_name":"Anode Current","value":"4.5","numeric_value":"4.5","unit":"mA","param_group":"typical_operating"},{"key":"ra","display_name":"Anode Resistance","value":"11200","numeric_value":"11200","unit":"Ω","param_group":"typical_operating"},{"key":"gm","display_name":"Transconductance","value":"1.3","numeric_value":"1.3","unit":"mA/V","param_group":"typical_operating"},{"key":"mu","display_name":"Amplification Factor (μ)","value":"14.5","numeric_value":"14.5","unit":"—","param_group":"typical_operating"}]}],"synced_at":"2026-04-07T12:07:12.422Z"}