
500 - 20 - 11
3
+
RS
3.9k
100
-
+
1
5
4
8
33k
200
RE
33
2.2k
6
3
2
7
100
100k
S1
10
+
0.033
10
+
10
S2
VB = 1.5 VDC
RB = 4.7
1k
IL
VO
All resistors in ohms, all capacitors in
F unless otherwise stated
Fig. 1 Test Circuit
All resistors in ohms, all capacitors in farads unless otherwise stated
U.S. Patent No. 4,034,306 - Patented in other countries
Fig. 2 Functional Schematic
MPO
OUTPUT
VB
RE
GND
200
33k
VOLUME
CONTROL
INPUT
100
VMIC
30k
2.2k
27k
6
5
3
2
4
7
8
1