Advertisement
eA _ cincurt¢ CONFIGURATION
les
"AS. 'fown, in the block cea this circuit is scone ear =
oe Gee 'of: the 2 units. Alt the. preamplifier the input stage
" consists. of the ICL (Input capacitorless) differential ampli-- =
- > fier. and. the current mirror circurt while: the next stage is. ie
composed of a class A in the Darlington connection, "and. a
ee ae
ee
Like the. epee 'the tone 2 amplifier i is in the cae
Be py deck coupled, 2- stage circuit configuration. The load i in the © -
: ~ second stage is. led from the constant current circuit for the
|
ee prevention of supply a
fluctuations and the improve- ie Bae
Pe es
-
2
Dae e a e "are the. same. 'elements, 'the' operating currents: of Od? and zee
Rae ment of current availability.
he: differential circuit "consists. of 3 stages. The. power:
- EQUALIZER A AMPLIFIER
ie
circuit. In: the second. stage. is: in 'the: Darlington. connec:
diferent
e ine flor
'tion which. assures | a. high" gain.
ee
oe
ee employs: a constant: ze current. ch cuit for. 'the stability of oleae as
: oo Cuit: performance eG. The output stage employs a pure com: a 7 e =
|
: _ plementary circuit: 'to. Jower. the ou: iput impedance.
; he a ' oot
:
equalizer. Cire uit is: designed t to operate v without being influ. a
oe
me "ene ed. I by: the load effect. ee
ees
ee
ee
2 Current mirror. Class A with
ee
Wee Be
eres
a teristic. of. Dd;
_
Teason, a-cor nstant: current circuit is: employed.
ete
eo
|
[his circuit is devised to maintain. a constant emiter:
0 60
ae ee v
ge (VBE) | anda constant | ig, thus maint ainiag -
Do ae
: Ghee
|
es value" as a result: AS. is. 'recognized feo thy en ee
oo
totic characteristics of: the transistor, the VBE-iB- chirace
tae Ba is also maintained ¢ constant.
ee
a
so
CURRENT MIRROR ciRCUIT
Operation
CEG
ie see
tag de te ae
» hye eae
eae
ese
Te: 'operating currents nor Odi and. 043 are , preset ro : ie
ee the VGs: The drain current of Qd1 flows through Qd5 and..."
i: that of Qd3 flows: through Dd1. Qd5 is a constant: current... ,
ee sircuit. which jis biased. by Dd1. and Rd19. Therefore, the
base. potential. of Od5 is controlled by Dd? and Rd19. ; ts
_ Since both. Rdt7. and. Rd19- in. the current. mirror circuit ot
"In the power amplifier the input stage employs a single
__ Od3 are identical with each other, provided that the VBE-IC
ae tip' of dual FET. to obtain a 'uniform thermal characteristic.
he
charac teristic of Qd5- s identical with: the Vo: 1 charac
Thus the Od3 current varies in the same. —
~~ amplifier contains the ASO. and bias circuits and also. the aoe -manner as the. Od1 Cu rrent does, just. 'as it is: 'cast' on the
oe. protection circuit,
7 mirror. 'The: Od1 and Qd3 elements, are. always under aes =
4 balanced condition and the 2 DC stability 1S assured.
les
heed
- intréase > "Base potential.
ate
wr,
e e . 0 controlled.
(drop)
ea
ee
. Was. 3
oot
oe
. increase ye
Lee. Differential
:
amplifier
CONSTANT: cur RENT cl RCUIT
an the. EEL amplifier, 'the camp oe gain is isexpresed
Fo: obtain. a higher jairh,. 2.
The current mirror: circuit is 'composed: of ads: nde fs vat
: Od1. it iS a type of constant- current circuit which functions } oe : |
|
to. increase the gain. Tt it is used in the input stage, the SN. ann |
ratio. in. the: input stage, is increased and noise is. reduced. et
"On: the other haid a ok |
Advertisement
