mousa

New fridge models contain an alarm to notice door leaves open, it prevent energy losing. This circuit is a simple fridge door alarm that active when the fridges door leaves open for 15 seconds, this delay time depend on 10uF capacitor so you can increase this delay time by increasing the capacitor value. Alarm sound frequency depend on second capacitor value. The circuit run with 9v battery and draw 40mA when the alarm is active and lower than 10mA when it is in standby state. Its better to use a rechargeable 9v battery. Parts list: IC555 (2pcs) Buzzer LDR Resistor 1M Resistor 1.5M Resistor 100K Capacitor 10uF Capacitor 220nF Battery 9v

This circuit is an electric zapper that can convert 1.5v to very high voltage, so it can used as a fly killer. you have to connect two thin metal grid to the output exactly look like to commercial fly zapper. output voltage can reach to more than 2000v. You can use almost any other PNP transistor rather than S8550 and any other NPN transistor rather than S9013. The circuit run with 1.5v and consume 40mA to 100mA. Parts list: Transistor S9013 Transistor S8550 Resistor 30K Capacitor 100nF Capacitor 2uF 400v (8pcs) Diode 1N5408 (8pcs) Transformer 6v Battery 1.5v  Two thin metal grid

This is a very useful timer that can run 110/220v AC load up to 10A. This circuit give 5 time periods from 1 minute to 60 minutes, you have to select the time by time selector switch then press START to activating the relay for running the AC load and turning OFF the load after selected time automatically.  Maximum time period in this timer is 60 minutes but if you need to higher period so you have to increase the value of 470uF capacitor or 4M resistor to higher value.  If you need this timer for DC loads so can use second circuit diagram. Parts list: IC 555 Transistor 2N5551 Relay 12v Red LED Green LED Push switch  Selector switch Diode 1N4007 Bridge diode 1A Zener diode 12v 1W Capacitor 470nF 400v Capacitor 220uF 16v Capacitor 100nF Capacitor 470uF 16v Resistor 270 ohm 2W Resistor 30K Resistor 1K(3pcs) Resistor 100K Resistor 500K Resistor 1.5M Resistor 2M Resistor 4M

This circuit is a simple inverter that convert 1.5v to high voltage.  Parts list: Transistor BC547 (Transistor Kit https://goo.gl/5csLJy ) Transistor BD140 Transformer 220v:6v Capacitor 100nF (Ceramic Capacitor kit https://goo.gl/q29Du3 Resistor 30K (Resistor kit https://goo.gl/p4JvQY ) Please subscribe to my YouTube channel here:  https://www.youtube.com/c/EngMousaalkaabi?sub_confirmation=1  

There are different elements to electronic temperature measuring such as LM35, NTC, PTC, 18B20 and even diode 1N4148, some of them have very high precision in temp. measuring and some other have low precision and used only for detect if the temperature is cold or hot. Following circuit is simple way to using NTC, when the temperature raise over a certain temp.(more than 41C when the potentiometer set in mid level ) NTC's  electric resistance decreased and run the transistor for running the buzzer or any other load. Potentiometer using for set the temperature level that buzzer active. you can use any other NPN transistor for this circuit. The circuit works by 5v and consume lower than 10mA when the buzzer be turn ON. Parts list: Transistor S9013 NTC 10K Buzzer Potentiometer 1K Resistor 470 ohm