Please help me with Emitter Follower Voltage Regulator.
This is the explanation about operation of this circuit from http://www.circuitstoday.com/zener-controlled-transistor-voltage-regulators
" Let the supply (or input) voltage increase which will cause the output voltage Vout to increase. An increase in output voltage Vout will result in decrease of VBE because Vz is fixed and decrease in VBE will reduce the level of conduction. This will lead to increase m the collector-emitter resistance of the transistor causing an increase in collector to emitter voltage and as a result the output voltage will be reduced. Thus output voltage will remain constant. Similar explanation can be given for decrease in supply voltage."
Can anyone help me explain about when input voltage increase will cause the output voltage Vout to increase"?
I think that when Vin increase then the voltage drop across resistor R increase. And because the R is constant, current through it Ir= Ib + Iz will increase.Because Ir increase, there are at least one of two terms Ib, Iz increse but how can I know which current increase or both of them increase.If Ib increse then Ie increse and Vout increase, but I don't know how Vout will increase if I only Iz increase.
This is the explanation about operation of this circuit from http://www.circuitstoday.com/zener-controlled-transistor-voltage-regulators
" Let the supply (or input) voltage increase which will cause the output voltage Vout to increase. An increase in output voltage Vout will result in decrease of VBE because Vz is fixed and decrease in VBE will reduce the level of conduction. This will lead to increase m the collector-emitter resistance of the transistor causing an increase in collector to emitter voltage and as a result the output voltage will be reduced. Thus output voltage will remain constant. Similar explanation can be given for decrease in supply voltage."
Can anyone help me explain about when input voltage increase will cause the output voltage Vout to increase"?
I think that when Vin increase then the voltage drop across resistor R increase. And because the R is constant, current through it Ir= Ib + Iz will increase.Because Ir increase, there are at least one of two terms Ib, Iz increse but how can I know which current increase or both of them increase.If Ib increse then Ie increse and Vout increase, but I don't know how Vout will increase if I only Iz increase.
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