The timer project uses a dual 555 timer, which once started by pressing the button illuminates an LED until the desired time out period has elapsed when a buzzer is sounded. The duration of both the delay and buzzer sound period can be determined by the student and are easily adjusted by PCB mounted potentiometers. This allows the board to be used for a variety of applications, such as an egg timer or a timer for a game. (Max time period 200 seconds, max buzzer period 10 seconds)
This kit contains:
- 1 x PP3 clip lead
- 1 x 4AA battery holder
- 1 x slide switch
- 1 x push to make switch
- 1 x 556 (daul 555) timer IC
- 1 x 14 pin IC holder
- 1 x piezo buzzer
- 3 x 10nF capacitor, ceramic
- 2 x 100uF capacitor, electrolytic
- 1 x 330ohm resistor
- 2 x 10Kohm resistors
- 1 x 1Mohm resistor
- 1 x 100Kohm potentiometer
- 1 x 1Mohm potentiometer
- 1 x 5mm red LED
- 0.5m connecting wire
- 1 x timer PCB
PCB dimensions: 54mm x 46mm.
Requires x4 AA batteries, available separately.
Click here to download build instructions 
Note: Schools will receive a more detailed set of teaching notes on a CDROM.
