Newnes Circuit Calculations Pocket Book

Filters and attenuators 325

Example 17 Given that R

x

and R

2

in Figure 18.16 are 450 and

600 ft respectively, and that the attenuation N is 10, calculate the

values of R

A

, R

B

and R

c

-

10

99

R

A

= ^450 x - 2V^450 x 600 ^ x

= 459.09 - 104.97 = 354.12 ft

R

B

= 104.97 H

R

c

= (600 x — | - 104.97 = 507.15 ft

V 99/

10 PRINT "PROG 282"

20 PRINT "ASYMMETRICAL T ATTENUATOR"

30 INPUT "ENTER Rl" ; Rl

40 INPUT "ENTER H2" ; R2

50 INPUT "ENTER ATTENUATION" ; N

60 LET X=Rl*((N*2+l)/(N*2-l))

70 LET

Y =

2*SQR(R1*R2)*(N/(N*2-1 ))

80 LET Z=R2*((N

A

2+1)/(N*2-1))

90 LET RA=X-Y

100 LET RB=Y

110 LET RC=Z-Y

120 PRINT "RA = " RA "OHMS

130 PRINT "RB = " RB "OHMS"

140 PRIN