(Solved): The final step is to simulate your amplifier with the actual Norton Mic input and Earpiece output v ...
The final step is to simulate your amplifier with the actual Norton Mic input and Earpiece output
v_(L). Fig. 17. Norton Equivalent Mic input and Earpiece output attached to amplifier The Mic input
v_(M)is replaced with its Norton Equivalent current source. Note that the mic will draw DC current
∼0.2mAfrom the
+-V_(cc)supplies as in Q1. The Earpiece output
v_(L)is drawn using a loudspeaker symbol, which can be treated as a load resistance
R_(L). The typical value of
R_(L)~~32\Omega . Recall that
v_(I )has two components (
DC+AC), and both will be amplified to become
v_(o)=V_(o)(DC)+V_(o)(AC)To prevent DC current from Vo damaging the Earpiece, we also need to add a large electrolytic
ACcoupling capacitor
C_(c)in series with the Earpiece. Electrolytic capacitors are polarized, so any DC bias across it must match the polarity shown by the symbol: If the DC bias exceeds the capacitor's voltage rating, or if the capacitor is reverse biased, the electrolyte could break down causing the capacitor to explode! Fig. 18. Difference between Ceramic and Electrolytic Capacitors a) Verify whether the absolute DC bias across
Ccis
<1V, which will be safe.
