In this theoretical article we will try to solve as easier as possible a generic first order differential equation.
This equation is always there to ruin our days 😆
If you try to solve a simple RC circuit is there and waiting for you.
It is quite annoying how many times you will find it at your way so we decided to solve this equation even for people who does not have a lot mathematical knowledge.
This is a generic First Order Linear Differential Equation
Another way to remember it is
So as you can see it is a first order differential equation since the y function is only derivated once.
The etching is the technique that a strong acid chemical solution "eats" the unprotected copper.
So the etching method can be used for the production of printed circuit boards (PCB) since acid can be used to remove the unwanted copper from a copper clad.
A nice and easy method in order to make printed circuits at home is to use the so called : "toner transfer method". This method will be discussed in another article.
For now keep in mind that you have a copper clad (fr4) with the circuit "printed" (with toner) on it.
So this printed copper board can be etched with an acid solution called etchant.
This acid solution will eat all the unprotected toner and the remained, protected by the toner, copper will be our final printed circuit.