{"openapi":"3.1.0","info":{"title":"BJT Transistor API","version":"1.0.0","description":"Bipolar-junction-transistor (BJT) circuit maths as an API, computed locally and deterministically. The currents endpoint relates the three terminal currents through the DC current gain β (hFE): the collector current Ic = β·Ib, the emitter current Ie = (β+1)·Ib and the common-base gain α = β/(β+1) ≈ 1, from β and any one current. The bias endpoint analyses the operating point of the classic voltage-divider bias network — from the supply voltage, the two divider resistors, the collector and emitter resistors, β and the base-emitter drop it computes the Thévenin equivalent (Vth = Vcc·R2/(R1+R2), Rth = R1‖R2), the base current Ib = (Vth − Vbe)/(Rth + (β+1)·Re), the collector and emitter currents, the collector-emitter voltage Vce and the node voltages, and classifies the operating region as cutoff, active or saturation. The power endpoint computes the transistor's power dissipation, Pd ≈ Vce·Ic (plus Vbe·Ib), to check it against the rated maximum. Currents are in amperes, resistances in ohms and voltages in volts, with Vbe defaulting to 0.7 V for silicon. Everything is computed locally and deterministically, so it is instant and private. Ideal for electronics, amplifier-design, embedded and hobbyist app developers, biasing and operating-point tools, and electronics education. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is BJT biasing; for op-amp circuits use an op-amp API and for an LED series resistor an LED-resistor API.","contact":{"name":"PremiumApi","url":"https://www.oanor.com/by/premiumapi"}},"servers":[{"url":"https://api.oanor.com/transistor-api","description":"oanor gateway"}],"tags":[{"name":"Transistor"},{"name":"Meta"}],"components":{"securitySchemes":{"oanorKey":{"type":"apiKey","in":"header","name":"x-oanor-key","description":"Get your key at https://www.oanor.com/developer/keys"}}},"security":[{"oanorKey":[]}],"paths":{"/v1/bias":{"get":{"operationId":"get_v1_bias","tags":["Transistor"],"summary":"Voltage-divider bias","description":"","parameters":[{"name":"supply_voltage","in":"query","required":true,"description":"Vcc (V)","schema":{"type":"string"},"example":"12"},{"name":"r1","in":"query","required":true,"description":"R1 (Ω)","schema":{"type":"string"},"example":"47000"},{"name":"r2","in":"query","required":true,"description":"R2 (Ω)","schema":{"type":"string"},"example":"10000"},{"name":"rc","in":"query","required":false,"description":"Collector resistor Rc (Ω)","schema":{"type":"string"},"example":"1000"},{"name":"re","in":"query","required":false,"description":"Emitter resistor Re (Ω)","schema":{"type":"string"},"example":"220"},{"name":"beta","in":"query","required":true,"description":"β (hFE)","schema":{"type":"string"},"example":"100"},{"name":"vbe","in":"query","required":false,"description":"Base-emitter drop (V)","schema":{"type":"string"},"example":"0.7"}],"security":[{"oanorKey":[]}],"responses":{"200":{"description":"OK","content":{"application/json":{"example":{"data":{"note":"Voltage-divider bias: Vth = Vcc·R2/(R1+R2), Rth = R1‖R2; Ib = (Vth−Vbe)/(Rth+(β+1)Re). A mid-rail Vce (~Vcc/2) gives the most symmetric swing.","vb_v":1.724924,"vc_v":7.38738,"ve_v":1.024924,"vce_v":6.362455,"inputs":{"r1":47000,"r2":10000,"rc":1000,"re":220,"vbe":0.7,"beta":100,"supply_voltage":12},"region":"active","base_current_a":4.6126205e-5,"emitter_current_a":0.0046587467,"thevenin_voltage_v":2.105263,"collector_current_a":0.0046126205,"thevenin_resistance_ohm":8245.614},"meta":{"timestamp":"2026-06-05T11:30:23.863Z","request_id":"3543df5a-5cb2-4bc6-a70c-68950d3c0023"},"status":"ok","message":"Voltage-divider bias","success":true}}}},"401":{"description":"Missing or invalid x-oanor-key header"},"402":{"description":"Active subscription required"},"429":{"description":"Rate-limit or monthly quota reached"},"502":{"description":"Upstream did not respond"}}}},"/v1/currents":{"get":{"operationId":"get_v1_currents","tags":["Transistor"],"summary":"BJT currents","description":"","parameters":[{"name":"beta","in":"query","required":true,"description":"Current gain β (hFE)","schema":{"type":"string"},"example":"100"},{"name":"base_current","in":"query","required":false,"description":"Base current Ib (A)","schema":{"type":"string"},"example":"0.0000461"},{"name":"collector_current","in":"query","required":false,"description":"Or collector current Ic (A)","schema":{"type":"string"}}],"security":[{"oanorKey":[]}],"responses":{"200":{"description":"OK","content":{"application/json":{"example":{"data":{"note":"BJT current relations: Ic = β·Ib, Ie = Ic + Ib = (β+1)·Ib, and the common-base gain α = β/(β+1) ≈ 1.","alpha":0.99009901,"inputs":{"beta":100,"base_current":4.61e-5},"base_current_a":4.61e-5,"emitter_current_a":0.0046561,"collector_current_a":0.00461},"meta":{"timestamp":"2026-06-05T11:30:23.972Z","request_id":"1c2e703e-574d-445d-81ed-0436f97b2818"},"status":"ok","message":"BJT currents","success":true}}}},"401":{"description":"Missing or invalid x-oanor-key header"},"402":{"description":"Active subscription required"},"429":{"description":"Rate-limit or monthly quota reached"},"502":{"description":"Upstream did not respond"}}}},"/v1/power":{"get":{"operationId":"get_v1_power","tags":["Transistor"],"summary":"Power dissipation","description":"","parameters":[{"name":"vce","in":"query","required":true,"description":"Vce (V)","schema":{"type":"string"},"example":"6.37"},{"name":"collector_current","in":"query","required":true,"description":"Ic (A)","schema":{"type":"string"},"example":"0.00461"},{"name":"vbe","in":"query","required":false,"description":"Vbe (V)","schema":{"type":"string"},"example":"0.7"},{"name":"base_current","in":"query","required":false,"description":"Ib (A)","schema":{"type":"string"}}],"security":[{"oanorKey":[]}],"responses":{"200":{"description":"OK","content":{"application/json":{"example":{"data":{"note":"Transistor power dissipation Pd ≈ Vce·Ic (+ Vbe·Ib). 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