MAE 140: Linear Circuits – Winter 2013 Circuit Demonstration #3

Audio Mixer

What is an audio mixer?

1

ALM324N

2

BLM324N

3

CLM324N

100K

R1

100KR2

100KR3

100K

R4

100K

R5

22KR7

100KR6

GNDGND

GND

100KR9

100KR10

GND

22KR8

GND

Vin1

Vin2

VoutV1

V2

2-channel audio mixer using LM324

R9V1= 1+ Vin1R7

⎛ ⎞⎜ ⎟⎝ ⎠

R10V2= 1+ Vin2R8

⎛ ⎞⎜ ⎟⎝ ⎠

Vout=V1+V2

R9 R10Vout 1+ Vin1+ 1+ Vin2R7 R8

⎛ ⎞ ⎛ ⎞= ⎜ ⎟ ⎜ ⎟⎝ ⎠ ⎝ ⎠

Circuit close-up

Experiment Setup