Make: Electronics Chp2 Experiment 11

Experiment 11 “Light and Sound” is a continuation of Transistors.  The experiment itself is broken up into several phases whereas the first consists of a circuit that flashes an LED on and off for approximately one second.
The next phase of the circuit introduces a coupling capacitor which in turn creates a pulsating effecting via the implementation of an RC network. The difference between the two is that the LED is pulsing as a result of how the capacitor is discharged through the adjoining resistors. 

Additionally, more modifications to the circuit can be added such as one which produces a second network similar to the first. This second network drives an audio section of the circuit. Unfortunately, I did not have a speaker that would work to complete this part of the experiment.

Nonetheless, I found the experiment to be quite satisfying as it relates to the overall intent and purpose.  As for the beginner, there are definitely some possible challenges but nothing that cannot be overcome with patience and refreshing one’s self with the prior topics if need.

For example, unless you have extremely small hands, I wholeheartedly advise using needle nose pliers to build the circuits in this section. Secondly, the idea is to come away with an understanding of how oscillation works while getting you to think more deeply as to what type of applications circuits of this nature could be best suited for.

Therefore, a general understanding of the previous material related to transistor switching and the charging and discharging of a capacitor will serve you well in your understanding of this experiment.


Of note: I have quite a few electronic components lying around in addition to kits I’ve bought over the years. However, when it came to the 0.01uf and 0.33uf capacitor, I actually ended up finding those values in my Mylar capacitor set(cap codes 103 and 334 respectively speaking). Those capacitors are not pictured in this post.

Experiment 11 materials:
9-volt battery
Resistors 470k, 1k, 4.7k, 100K, 220k, 470k
Capacitors: 0.01uf, 0.1uf, 0.33uf, 1uf, 3.3uf, 33uf, 100uf, 220uf
Transistors: 2N2222
8-ohm Speaker

#Make #electronics #circuits #breadboard

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