Christmas LED Ring Oscillator using NPN and MOSFET transistors

Here is a simple three LEDs ring oscillator replaced NPNs with the MOSFETs. Use all LEDs with the same current or same type (color). RGB led will not work as you can expect.

Schematic:

LED ring oscillator using NPN and MOSFET transistors

Update.

Two LEDs oscillator based on 2n3904 transistors and LDR

LDR light sensitive switch

Here is a simple solution when you need to power off your circuit by light. It works!

RF Stage for Regenerative Radio Receiver

Regenerative Radio Receiver

I spent some summer time to build the World War II Regen Radio. Historical gadget! Yep, it's working!

CS50. Greedy

My code can be optimized, however, for better understanding, I left it as is.

/**
 * CS50: Greedy
 * Aleksey M.
 * 29.04.17
 *
 */

// Compile: clang -o greedy greedy.c -lcs50
// Run: ./greedy
// Check cs50: check50 2014.fall.pset1.greedy greedy.c
// Check cs50 style: style50 <fileName>.c

#include <stdio.h>
#include <cs50.h>
#include <math.h>

#define QUARTER 25
#define DIME    10
#define NICKEL  5
// #define PENNY   1

int main(void)
{

    float cash;
    int cents;
    int countQuarter;
    int countDime;
    int countNickel;
    int countPenny;
    int sum;
    int balance;

    // Prompt user to set value
    do
    {
        printf("Hello! How much change do you have for me?: $");
        cash = GetFloat();

    } while (cash < 0);

    // Debug!
    // printf("Yep! %0.50f \n", cash);

    // Convert dollars to cents
    cash *= 100;

    // Round the value and casting the "double" type of round() to "int"
    cents = (int) round(cash);

    // Check quarters
    countQuarter = cents / QUARTER;
    balance = cents % QUARTER;

    // Check dimes
    countDime = balance / DIME;
    balance = balance % DIME;

    // Check nickels
    countNickel = balance / NICKEL;
    balance = balance % NICKEL;

    // Check pennies
    countPenny = balance;

    // Sum
    sum = countQuarter + countPenny + countNickel + countDime;
    printf("%d\n", sum);

    return 0;
}