Make Electronics (10) Capacitator

This is the second part of my sketching/thought process for understanding the oscillator circuit in Experiment 8 in Make: Electronics.

I sketched out a simple oscillator circuit using a relay and a button.  When the button is pushed, the circuit is completed which pulls the switch up which then breaks the circuit letting the switch go back down again.  This process repeats very quickly until the button is released.

Here is the same circuit shown on a breadboard. (Note. The relay I'm using here is still the one that I carved up earlier.)

The relay is opening and closing so fast it sounds like a buzzer.


Next part of the experiment is to slow down the speed at which the relay opens and closes by adding a capacitor.

I put the capacitor in the circuit first without the LEDs to help keep it simple.  This is how I sketched it out.

This is what it looked like on the breadboard.  Push the button and I could hear the relay opening and closing at a slower rate.

Time to add in the lights.

Here's the sketch (same as the book) of the completed circuit.  LEDs added in along with a resistor to keep them from burning out.

Picture of the completed circuit.  The capacitor slows things down enough that you can see the lights blink.


I'm writing this several days after I worked it all out and I find I am still a little fuzzy on how the capacitator is hooked into the cirucit.  I need to go back and play a bit more with this setup to cement it in my mind.

Bear with me....my mind isn't as nimble as it once was.  If you are following along in the book and moving at a faster pace, check out Jim Kelly's Blog, he is much further along than I am. 

Previous Posts:

• Make Electronics (1)
• Make Electronics (2)
• Make Electronics (3) Radio Shack
• Make Electronics (4) The Toolbox
• Make Electronics (5) My First Experiments
• Make Electronics (6) More parts...More Money
• Make Electronics (7) Soldering 
• Make Electronics (8) Relays 
• Make Electronics (9) Sketching to Understand
• Make Electronics (10) Capacitator

[Images: All taken by Al Gunn: (CC: Attribution)]