METHOD OF DETERMINATION OF CURRENT LOCALISATION VOLTAGE IN POWERFUL HF AND UHF BIPOLAR TRANSISTORS Russian patent published in 2015 - IPC G01R31/26 

FIELD: electricity.

SUBSTANCE: method is based on use of known effect of abrupt change of curve steepness of voltage on emitter junction upon permanent emitter current dependence from collector voltage U_EB(U_C). The controlled transistor is connected as per diagram with common base. Permanent emitter current is set. To collector of the controlled transistor sum of linear increasing voltage not exceeding the maximum permitted value for the given type of transistors at set current, and KF cine voltage with low amplitude is supplied. Amplitude $${\tilde{U}}_{EB}\left(U_{C0}\right),$$ $${\tilde{U}}_{EB}\left(U_{C1}\right),$$ $${\tilde{U}}_{EB}\left(U_{C2}\right)$$ of variable voltage constant on emitter of the controlled transistor is measured at three voltages U_C0, U_CL1, U_C2 on collector of the controlled transistor, respectively, and required voltage of localisation is calculated by equation $$U_{CL}=\frac{U_{C2}-m{U}_{C1}}{1-m},$$ where $$m=\sqrt{\frac{a1-1}{a2-1}},$$ $$a1={\tilde{U}}_{EB}\left(U_{C1}\right)/{\tilde{U}}_{EB}\left(U_{C0}\right),$$ $$a2={\tilde{U}}_{EB}\left(U_{C2}\right)/{\tilde{U}}_{EB}\left(U_{C0}\right).$$ At that for steepness measurement of function U_EB(U_C) the low variable signal is used ensuring increased accuracy of steepness measurement for the specified function.

EFFECT: exclusion of dangerous out-of-limit actions on the controlled device and determination of current localising voltage of powerful HF and UHF bipolar transistors without the controlled transistor setting to hot spot mode.

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