- #1

dancavallaro

- 13

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## Homework Statement

Here's a crude description of the problem until my attachment is approved: it's essentially a voltage divided connected to a common-emitter amplifier (I think). There's a +10 V line connected via an 8.4 kOhm resistor to the base of the NPN transistor, and a 1.6 kOhm resistor connecting the base to ground. Then there is a resistor R_load connecting the +10 V line to the collector of the transistor, and a 1.0 kOhm resistor connecting the emitter of the transistor to ground. I'm supposed to calculate the current through R_load, and say whether the result depends on the value of R_load. We're assuming the simplest model of a transistor: the base current is always 0, and when the B-E junction is forward-biased at least 0.6 V, then current flows from C to E, where V_E = V_C - 0.6.

## Homework Equations

When V_BE > 0.6:

I_C = I_E and V_E = V_C - 0.6

## The Attempt at a Solution

I think V_B = V_in*(1.6/(1.6+8.4)) = 1.6 V, so the B-E junction is forward-biased, and current flows from the collector to the emitter. Then V_C = 10 - I_C*R_load, but I_C = I_E so V_C = 10 - I_E*R_load. Then V_E = V_C - 0.6, so V_E = 9.4 - I_E*R_load. Then I_E = (9.4 - I_E*R_load)/1000, so I_E = 9.4/(1000+R_load). But I don't think this is right, because I'm pretty sure the current through R_load doesn't depend on the value of R_load. What am I doing wrong here?