Thames & Kosmos Electronics - Changing the flashing speed

EXPERIMENT 

Changing the
flashing speed
YOU WILL NEED
 your flasher circuit from
Experiment 12
  resistor, . kΩ
As soon as you have replaced the red
battery wire, the two LEDs flash in rapid
succession! So you have shortened the
flash duration.
 WHAT’S HAPPENING?
HERE’S HOW
1. Take your flasher circuit from
Experiment 12 and remove the red
wire from the positive battery
terminal. Park it in one of the
board’s compartments.
2. Now make the following changes in
accordance with your new
assembly plan: Remove the 22-kΩ
resistor (R1) and the 220-kΩ resistor
(R2). In their place, insert the 3.3-kΩ
resistor for R1, and the 22-kΩ
resistor for R2.
3. Replace the red battery wire.
What do you notice?
+
–
9V
T2
T1
R 2
22 kΩ
+
10 µF
C 2
+
100 µF
C 1
LED 1
R 4
470 Ω
R 3
470 Ω
R 1
3.3 kΩ
LED 2
LED1
LED2
T1
+
–
T2
A
A
C
C
C1  µF
R3  Ω
R
 Ω
R2
 kΩ
C2  µF
R
. kΩ
+
+