14
PICAXE-08 ALARM PROJECT
revolution
© copyright 2002 - AXE102 Alarm Student Project Notes Version 1.1
Revolution Education Ltd. Email: [email protected] Web: www.rev-ed.co.uk
14
Supported by:
Testing the transistor using a buzzer
A buzzer could be connected as an output device as in this cicruit.
After connecting the buzzer it can be tested by a simple
program like this:
main:
high 4
wait 1
low 4
wait 1
goto main
This program would switch the buzzer (connected to
output pin 4) on and off every second. If the buzzer does
not sound check that:
1) the diode is connected the correct way around
2) the correct resistors are used
3) the transistor is connected the correct way around
4) the buzzer red wire is connected the correct way around
5) the correct output pin number is being used in the program
6) all the solder joints are good
Output Devices
Output devices that can be connected via a transistor include buzzers, motors, solenoids,
sirens and flashing strobe lights. However some devices may need a higher power
transistor - in this case the Darlington transistor BCX38B can be used instead of the
standard BC548B transistor.
0V
pin
1k
Buzzer
BC548B
V+
1N4001
(red)
start
high 4
wait 1
wait 1
low 4
