Valentine Heart Project

This project flashes 18 LEDs at three different rates and you can use these to create an eye-catching
Valentine Heart! The circuit is kept simple (and low cost) by using the 4060B IC which is a counter and
oscillator (clock) in one package. The circuit requires a 9V supply, such as a PP3 battery. It will not work
with lower voltages and a higher voltage will destroy the LEDs.

The preset variable resistor can be used to adjust the oscillator frequency and this determines the flash
rate of the LEDs. The IC limits the current to and from its outputs so the LEDs can be safely connected
without resistors in series to limit the current. The stripboard part of the circuit is easy to build but the
wiring for the LEDs needs care so detailed instructions are provided below.
You can download the Valentine Heart template to print out and glue onto thick card, hardboard etc.

Using a battery (or power supply) with a voltage higher than 9V will destroy the LEDs.

You can see from the circuit diagram (below) that 6 LEDs are connected in series between the +9V supply and 0V.
Each LED requires about 2V across it to light, so using a voltage of about 12V (= 6 × 2V) or more will make the LEDs
conduct directly, regardless of the 4060B IC. With no series resistor to limit the current this will destroy the LEDs.

Circuit diagram

Parts Required

  • resistors: 10k, 470k
  • preset: 47k (this could be 100k if necessary)
  • capacitor: 0.1µF
  • 4060B IC
  • 16-pin DIL socket for IC
  • LEDs × 18, 5mm diameter, red (or any mix of red, orange, yellow and green)
  • on/off switch
  • battery clip for 9V PP3
  • stripboard 13 rows × 18 holes  


Circuit diagram by Circuit Wizard

Download this diagram

To Download circuit wizard

Circuit diagram by LochMaster

To Download LochMaster ( soon )

PCB Layout by Circuit Wizard

Download this PCB

To Download circuit wizard

Valentine Heart Template

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