Nokia 3105 Servicehandbuch

CCS Technical Documentation

System Module

RH-48

Issue 1 11/2003      Confidential         ©

2003 Nokia Corporation

Page 11

used to control average current going through LEDs. A step-up converter and a constant 
current source is used to ensure that the LEDs provide uniform intensity and color.

Introduction

Vibra is located on the D-cover and is connected by spring connectors on the PWB. It is 
located in the bottom of the engine.

Interfaces

Vibra is controlled by pwm signal VIBRA from UEM. This signal allows control of both 
frequency and pulse width of signal. Pulse width is used to control current when battery 
voltage changes. Frequency control searches for optimum frequency to ensure silent and 
efficient vibrating.

The 13 mm speaker capsule that is used in DCT3 products also is used in . The speaker is 
dynamical—very sensitive, and capable of producing relatively high sound pressure at 
low frequencies. The speaker capsule and surrounding mechanics comprise the earpiece.

The microphone is an electric microphone with omnidirectional polar pattern. It consists 
of an electrically polarized membrane and a metal electrode, which form a capacitor. Air 
pressure changes (i.e., sound) move the membrane, which causes voltage changes across 

the capacitor. Since the capacitance is typically 2 pF, a FET buffer is needed inside the 
microphone capsule for the signal generated by the capacitor. The microphone needs 
bias voltage as a result of the FET. 

Musical Instrument Digital Interface (MIDI) defines the data interchange format. By 
implementing MIDI engine, enriched sound effect will be achieved, which includes: ring-
ing tones, UI event sounds, and music for games and entertainment. 

Rated DC voltage

1.3

V

Rated speed

9500 

± 3000

rpm

Rated current

115 

± 20

mA

Starting current

150 

±  20

mA

Armature resistant

8.6

ohm

Rated DC voltage available

1.2 to 1.7

V

Starting DC voltage

min 1.2

V