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Hello again! in the first part we've seen how the basic 24h clock works (the hour coulmn counts to 24 and then resets to 00). It was quite easy and there were no problems, but let's extend the idea a little bit. What if we want to design a 12h clock?  well.. it's the same idea but there was a little problem which is: when the hours reachs 12 and counts to the end of the hour 12.59 we don't want it to reach 13, we rather want it to reset to...? 01 not 00 so i had to make a small trick you'll see later. How the circuit works? It's the same circuit as the first part   but we've to edit the hours coulmn so it resets to 00 when it reachs 13 and then clocks the first coulmn of hours so it becomes 01 .. simple! So that's how i made it , the two AND gates U9 and U10 detect the case when the hours coulmn is 13 and their output(A) then will be 1.  Output A has two jobs to do : - The first is to reset the boths hours coulmn so it's

I ntroduction We can divide regulators into two major types : Linear regulators Switching mode regulators In this article, we will introduce you to the linear regulators and then we will get to the magical switching supplies! Linear regulators Fig.1 Linear regulator shown in fig.2 produces DC regulated output from a higher DC input supply by simply putting a transistor in series between the input and the output. Fig.2 This series transistor  (called “ series–pass transistor ” or simply “ pass transistor ”) is operated in the linear(ohmic) region of its VI curve. That’s it,  Transistor Q1 acts as a variable resistance that drops the excess voltage across it. So it can be represented as shown in fig.3 . Fig.3 Using simple math, the voltage drop across the resistor is the difference between input and output voltages (this term is called the “headroom”) V = V (in)-V(out) If we want to calculate the dissipated (wasted) p

This photo is from this instructables project here There are many stuff on the internet about this project, but we are gonna add something or two. This circuit was a school project and it was a 24h clock, but i decided to extend it to 12h and 24h with the transferring between them using a switch so you can choose whatever mode you want. Anyway, i made this circuit just for fun so i just simulated it on proteus, i.e we're not going into pcb design. The final project First of all we're going to divide this tuorial into 3 parts: - How it works in the 24h mode. - How it works in the 12h mode. - How to transfer between them using simple switch. So... let's get started with the first one..