Publicité
111.4.
1.4.
11.4.
Tel lermotorverstarker
Platter Motor
lifier
The two sinusoidal
signals produced by the platter motor oscillator are
boosted
to the necessary
power
level
by the platter motor amplifiers.
Each
amplifier
is built around an integrated circuit
(Z 201/202)
that affords
high
voltage gain. A four transistor push-pull
power stage follows.
The gain of
this stage is set to approximately 6 dB by the associated
1 k resistors,
there-
by doubling the output voltage of the IC and enabling motor drive voltages
of over 10 volts RMS to be produced. Ihe overall
amplification of each platter
motor
amplifier
is determined
by the RC feedback
network
between
the output
{connections C 7/8) and the inverting
input
(pin 2) of the IC. The capacitor
C 209/213 increases the amplification at higher signal frequencies;
the
resulting
increased output voltage
is necessary
to compensate
for reducec
inherent motor efficiency at 45 and 78 RPM.
Amplificateur du moteur d'entrafnement du plateau
-27 -
Publicité
