Bipolar junction transistors

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1 Bipolar junction transistors Find parameters of te BJT in CE configuration at BQ 40 µa and CBQ V. nput caracteristic B / µa , 0,5 0,3 0,35 0,4 BE / V Output caracteristics C / ma B 0 µa CE / V C CB pf, f T 600 MHz

2 Calculation of parameters E BE 0 const B CE CEQ E BE BE 0 const CE B CE3 CE B BQ

3 3 Calculation of parameters E 0 E BE B CE const CEQ E Ω? E

4 4 Calculation of parameters E C C3 C 0 const B CE B3 B CE CEQ E C 0 const CE B BQ

5 5 Calculation of parameters 3 C C3 C (5. ) 0 E 0 const 6 B CE B3 B CE CEQ (70 0) 0 70

6 6 Calculation of parameters 3 C (3.6.9) 0 E 0 CE B const BQ ms

7 7 T- type model of te BJT Sketc te T- type model of te transistor in te middle frequency range. Find te parameters of te model. Considering transistor in an amplifier circuit (input AC voltage is 0 mv, load resistance is 000 Ω), find te AC output voltage and AC voltage gain.

8 8 T- type equivalent circuit of a BJT in its CE configuration r E kt q CQ 0.05 CQ r B B βr E r CE / E

9 9 Te T- type model of a BJT in its CE configuration r E β kt q CQ β 0,05 CQ f β f T / β 0 β 0 + jω / ω β r B E re ( + β) rce / E C β CE C C C E, CCE ( K)

10 0 Π - type model of te BJT Sketc te Π - type model of te transistor in te middle frequency range. Find te parameters of te model. Considering transistor in an amplifier circuit (input AC voltage is 0 mv, load resistance is 000 Ω) find te AC output voltage and AC voltage gain. Finis te model (add capacitances).

11 Te Π - type model of a BJT in its CE configuration C CQ g m 40 0,05 CQ 0 g C r CE ro... π β g m 00 CQ C C C r B E µ Cπ m C π f µ T r π g

12 Field effect transistors Find parameters of te FET at GSQ -0.4 V and DSQ 5 V, compose its model and find parameters of its elements. ttp://web.iot.dk/kbj/komponenter/datablade/n5457.pdf

13 3 Finding of FET parameters S g m 3 ( ) A/V

14 4 Finding of FET parameters r 0.5 o 3 ( ) 0 875kΩ

15 5 Finding of FET parameters S g m A/V

16 6 GS0, V, Dmax.05 ma. GSQ 0,5 V, DQ 0.4 ma. Finding of FET parameters S S g g DQ Dmax m GS Dmax GSQ m GS0 GS0.08 ma/v..0 ma/v. n general case: D S g S g K( m m GS K( ( GSQ GS0 GS DQ ), GS0 GS0 ) ( GS D GS0 ; ) ma/v. ) 0.5+.

17 7 Π - type model of te FET g r o m D D DS GS GS DS const const C C C f S S T C C C C C g m π( C+ CS)

18 8 Models of transistors. A BJT is in CE configuration. At te Q-point (wen base current is 0.5 ma and collector-emitter voltage is 5 V), te input resistance is 50 Ω, te base current gain is 0, te output conductance is 0, ms. Collector junction capacitance is pf. At frequency 0 MHz, te base current gain decreases to. Sketc te Π-type model of te transistor. Find parameters of te model elements. Considering transistor in an amplifier circuit (input AC voltage is 0 mv, its frequency corresponds to te midle frequency range (it is possible not take into account reactances), load resistance is 00 Ω), find te AC output voltage and AC voltage gain.. Sketc te T-type equivalent circuit, find parameters of te circuit, and repeat calculations of output voltage and voltage gain. 3. Comment on te results.