Nokia NHM-7 series Service Manual page 51

PAMS Technical Documentation
LEDs are controlled by the UEM PWM outputs. Both LEDs are controlled
by KLight output of the UEM. Current flow through the LEDS is set by
biasing the transistor and limiting the current by resistors. Current is set
separately to keyboard and LCD leds.
Internal Speaker
The internal earpiece is a dynamic earpiece with an impedance of 32
ohms. The earpiece is low impedance one since the sound pressure is to
be generated using current and not voltage as the supply voltage is re-
stricted to 2.7V. The earpiece is driven directly by the UEM and the ear-
piece driver in UEM is a bridge amplifier.
UEM
EARP
EARN
Issue 1 10/2001
22Ω
22Ω
27pF
E Nokia Corporation
System Module & UI
1000Ω@100MHz
1000Ω@100MHz
27pF
NHM–7
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