(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

you have a phototransistor that you have modeled as a Thevenin equivalent circuit. It has a output impedence(Thevenin Impedence) of 10kohm and produces a peak voltage o2 2V at a frequency of 80 MHz. The input impedence of the oscilloscope as this simple combination of input impedences.

a.draw the osilloscope/photodetector circuit

b. calculate the half power frequency

c. a 50 ohm resistor is added in parallel to the 1M ohm load. draw the new circuit.

d. calculate the new break frequency.

2. Relevant equations

[tex]f_b=\frac{1}{2\Pi R C}[/tex]

3. The attempt at a solution

1.The photodetector in parallel with the capacitor and 1m ohm resistor

2. I just took [tex]f_b=\frac{1}{2*\Pi*10^3 ohms*20^-9F}=81.40MHz[/tex]

3.The photodetector in parallel with the capacitor,1m ohm resistor, and 50 ohm resistor

4. not too sure

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# Homework Help: Phototransistor modeled as a Thevenin equivalent circuit

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