Is there a good visual way to see what capacitors & transistors do? While I’ve read the descriptions of what they do, I’m more of a visual person who would like an “ah ha” moment… Thanks!
Prior to teaching our freshman to program microcontrollers, we introduce them to basic breadboard electronics and try to emulate the functions of the microcontroller. It just so happens three of the simple circuits, the LED flip-flop, LED dimmer and transistor amplifier, help to demo the use of a transistor and capacitor. The advantage of using LED circuits, is that it gives you visual feedback. There are also a million other simple circuits that demo transistors and capacitors using things like buzzers, photo-resistors, etc…..I just happen to like these.
The first circuit, an LED dimmer, uses the capacitors ability to store electrical energy (like a battery) and discharge it through the circuit when the primary power is removed. I liked this site, because the author has the circuit’s output connected to a ‘scope and gives a nice visual to the falling voltage, although I don’t condone their breadboard tidiness.
The second circuit, the LED flip-flop, demonstrates the use of transistors to switch on and off a pair of LEDs. This action is controlled by the two base resistors and capacitors in the circuit (RC circuit). When you increase the value of the capacitors the switching frequency slows down and vice versa.
The third circuit, a transistor amplifier, shows a nice demonstration of using a transistor to amplify a high resistance input in order to light an LED. I liked the general description of how a transistor functions as well as using a darlington pair to produce a high-gain amplifier.
These are just two examples that help to visualize the components use. If you are interested in diving deeper, looking at things like filters, you might want to get a scope (i happen to like my DSO nano as it’s cheap and easy to use).
I hope this has helped to answer your question and good luck with your circuits!
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“Ask an Educator” questions are answered by Adam Kemp, a high school teacher who has been teaching courses in Energy Systems, Systems Engineering, Robotics and Prototyping since 2005.