The Maplin Electronic Circuits Handbook, 2nd Edition

92 AMPLIFIERS

ι

/v

2

22 k

10μ

Η IF

Input

TR,

BC184L

470

SET GAIN

τη

1 5

4k 7

TR

2

BC184L

fr

1

—+ 9 V

10μ

lh-°

/v

3

100k

1 k

Output

100 μ

I

-OOV

Figure 4.32 High-gain two-stage

amplifier

Input

R

i

Figure 4.33 Improved emitter

follower

is shown in Figure 4.33. This circuit still provides a voltage gain of unity

and zero phase shift. The transistors have been specified for low-noise

operation and this circuit is ideal for more critical applications such as

buffering a non-constant impedance filter from a high impedance input

source.

Photo 4 Simple low-power

output stage using a variable-

gain operational amplifier

stage followed by a

complementary pair ...