User Guide

CCS Technical Documentation System Module
RH-10
Issue 1 09/2002 Nokia Corporation Confidential Page 21
Buzzer
Introduction
The functioning principle for the buzzer is magnetic. The diaphragm of the buzzer is
made of magnetic material and is located in a magnetic field created by a permanent
magnet. The winding is not attached to the diaphragm as is the case with the speaker.
The winding is located in the magnetic circuit so that it can alter the magnetic field of
the permanent magnet, thus changing the magnetic force affecting the diaphragm.
This functioning principle makes the buzzer very efficient but also sensitive to external
magnetic fields. It should not be located close to transmitter power wires on PWB. Oth-
erwise, the transmitter current can be heard from the buzzer. The useful frequency range
is approximately 2 kHz-5kHz.
Battery
Phone Battery
Introduction
A 1000 mAh Li-ion battery (BLB-3) is standard in RH-10.
Interface
The battery block contains NTC and BSI resistors for temperature measurement and bat-
tery identification. The BSI fixed resistor value indicates the chemistry and default
capacity of a battery. NTC resistor measures the battery temperature. Temperature and
capacity information is needed for charge control. These resistors are connected to the
BSI and BTEMP pins of battery connector. Phone has pull-up resistors (R202) for these
lines so that they can be read by A/D inputs in the phone (see the following figure).
Resistor array (R206) is ESD protection. There also are spark caps in the BSI and BTEMP
lines to prevent ESD.
Batteries have a specific red line to indicate if the battery has been subjected to excess
humidity. The batteries are delivered in a "protection" mode, which gives longer storage
time. The voltage seen in the outer terminals is zero (or floating), and the battery is acti-
vated by connecting the charger. Batteries have internal protection for overvoltage and
overcurrent.
UEM
VFLASH1VANA VBAT
1n
C217
10k
R205/2
1n
C220
10k
R205/1
100k
R202/1
OVERCHARGE/
OVERDISCHARGE
PROTECTION
10p
C100
Ni-MH
VBATT
BSI
GND
BTEMP
Battery
connector
100k
R202/4