electrialstandards

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

Motor name plate consists of voltage range for operating motors. Operating the motors both lower and higher than motor name rating will leads to reduced efficiency and may also leads to premature failure of motors. Effects of low voltage on Induction motors   When voltage applied to motor get lower than name plate lower range of voltage than for fixed amount of power at lower voltage current drawn by motor get increased. Higher current will leads to exceeding motor name plate current rating that will leads to heating up the motor and even burning out the motor if over-current persists. Power in motor is = Voltage X Current X Power factor So lower the voltage higher will be current drawn by motor as power factor is same for motor. Effects of high voltage on Induction motors:-  There is often assumption made from Power relation that Since low voltage increases the current drawn by motors, then high voltage must reduce the current draw this lower current will leads to lower heating effect

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 power inverter that convert 1.5v to high voltage. output voltage is lower than 150v but can run a small 220v AC lamp (not full luminance).  I test it to running a 5W LED lamp. the circuit draw about 100mA to 200mA from the battery. you can see how it work in following video. Parts list: Transistor BC547 Transistor BD140 Transformer 220v:6v Capacitor 100nF Resistor 30K Note: Since the output voltage have high frequency so maybe harmful for multimeter voltage tester.

Now days electricity is backbone of everyone life. It seems life is electricity. There was most often curiosity in every human being that who discovered electricity and when. Let’s read article below to know how electricity was discovered. As everyone knows electricity is nothing but source of energy. Electricity is not invented as it is form of energy and was always present. It is only discovered and most people think that this is discovered by Benjamin Franklin but his experiments helps in getting a connection between lightning and electricity. Way back in 600 BC ancient Greeks discovered that “When we rubbing fur on amber it caused attraction between the two” thus we can say that they have discovered static electricity. There are so many discoveries has been made upto 17 th century such as:- 1.     Invention of electrostatic generator 2.     Difference between positive and negative currents 3.     Classification of materials as conductors or insulators. William Gilbert:- In 1600 y

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