Introduction

7-Segment displays are always interesting to electronic beginners. Various methods are there to interface 7-segment displays in circuits. 7-Segment displays are of two types.

• Common anode 7-segment display
• Common cathode 7-segment display

74LS47 is a BCD to 7-segment decoder/driver which can be used to interface common anode 7-segment displays in circuits. Here, we will see a module using 74LS47 by which we can make a 0-9 counter in few simple steps.

Package includes :

• PCB
• 74LS90
• LED – 4
• 1K resistor – 4
• Push button switch

Assemble the circuit as shown in the following image.

Circuit diagram of BCD/Decade counter using 74LS90 is shown below.

Working

Modules required

1. Voltage regulator module
2. Astable multivibrator module
3. BCD/Decade counter module

Step 1 : Power the BCD Counter module from a 5V regulator as shown in the following image.

Package includes :

• PCB
• 555 timer IC
• 10 Micro Farad capacitor
• 0.01 Micro Farad capacitor
• 10K resistor
• 1K resistor
• 1M POT
• LED

Assemble the circuit as shown below. Leave POT1 and R2 unconnected. POT1 is parallel to R1 and POT2 is parallel to R2. Only one from each set need to be connected.