Five Neat Little Projects

About: I am a photographer, a tinker, an electronics technology engineer, and author; I write short stories and poetry for the love of writing. I started writing poetry in high school over thirty years ago where I ...

Got to love circuits that flash and make noises when you are showing electronics to young people. These five circuits that take less than an hour to build and they are easy to modify in order to change the flashing speeds or on times.

The first circuit is a little different and a fun treat but first to parts.

Supplies:

Parts and Supplies

I have a few extra parts like capacitors just to change the speeds of the flashers and the on times.

3 x 100 Ω

1 x 330 Ω

2 x 470 Ω

3 x 10 KΩ

1 x 1 MΩ

1 x 1 KΩ pot

2 x 0.01 uF

2 x 0.1 uF

2 x 1 uF

2 x 100 uF

2 x 1000 uF

4 x BC547

1 x BC557

2 x 2N3904

1 x Chip RGB LED

4 x LEDs Any Color

1 x Momentary Button Switch

1 x Piezo Buzzer

Batteries or an adjustable power supply.

9 Volt Battery

9 Volt Battery Holder

3 x AA 1.2 Volt Rechargeable Batteries

1 x 3 x AA Battery older Bread Boards

If you make permanent circuits you will need prototype boards, a soldering iron, solder, and cutters, to remove excess leads.

Step 1: Beeping RGB LED

This first circuit is a real neat circuit, it uses the changing current of the chip RGB LED to make the piezo buzzer buzz with different tones as the LED changes color.

Parts

1 x chip RGB LED

1 x Piezo buzzer

1 x BC547 transistor

1 x 100 Ω

1 x 330 Ω

9 volt battery and holder Wire and bread board.

Step 2: Delay Circuit

This circuit will keep the LED on until the capacitor losses its charge. With this circuit I could change the brightness and the on time with different valued capacitors, resistors, and transistors.

Parts

1 x 100 Ω

1 x 10 KΩ

1 x 1000 uF

1 x 2N3904

1 x LED Any Color

1 x Momentary Button Switch

3 x AA 1.2 Volt Rechargeable Batteries

1 x 3 x AA Battery older Bread Boards

Step 3: Dimmer Circuit

This is a nice little circuit to demonstrate controlling an LED with a pot and a transistor.

Parts

1 x 100 Ω

1 x 2N3904 transistor

1 x 1 KΩ pot

1 x LED Any Color

9 volt battery and holder Wire and bread board.

Step 4: Flasher

This circuit is very forgiving and east to change the speed of the flashing by changing the value of the capacitor.

Parts

1 x BC547

1 x BC557

1 x LED Any Color

1 x 1 uF

1 x 1 MΩ

9 volt battery and holder Wire and bread board.

Step 5: Flip Flop Flasher

This is a very forgiving circuit; you can put the capacitors in backwards and the circuit works, you can also change the flashing speed by changing the capacitor values.

Parts

2 x 470 Ω

2 x 10 KΩ

2 x 100 uF

2 x BC547

2 x LED Any Color

9 volt battery and holder Wire and bread board.

Step 6: The Circuits in Action

Here is a video just so you can see the circuits in action.

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    4 Discussions

    0
    None
    Eric Caruyer

    6 days ago

    Very instructables !
    This is one of the first electronics lesson I understood.

    1 reply
    0
    None
    Josehf Murchisoniceng

    Reply 7 days ago

    My wife thought an animal was crying when I built the circuit with the RGB LED and the piezo buzzer. I'm tempted to see if it will attract foxes and wolves in the bush.