mousa

This circuit is a FM transmitter. can run it by 9v battery. the power consumption is very low about 10mA so a small 9v battery worked for long time. The frequency of radio must set between 88 to 93 MHz. The circuit contain trimmer for set frequency of transmitter. Part list: Transistor BC547(2pcs) Capacitor 10uF(2pcs) Capacitor 1nF(2pcs) Capacitor  5.6pF Trimmer 2-18pF Electret microphone Resistor 4.7k(3pcs) Resistor 100k Resistor 10k Resistor 270 ohm Coil 4mm diameter 5 turns air-core (2pcs) Antenna 10cm  

This circuit is an one axis solar tracker. Today this circuit used in modern solar street light and solar systems in homes for increasing the efficiency. I tested it and work well. Best dc motor for this circuit is cordless drill motor (without removing gearbox)because that is very powerful and can move your heavy solar panel easily. In following video you can see how it work, however i test it without solar panel. Parts list: IC LM324 LDR(2pcs) Transistor BD139(2pcs) Transistor BD140(2pcs) Potentiometer 100k potentiometer 10k Diode 1N4007(4pcs) Capacitor 100n Resistor 47k Resistor 15k DC Motor 6 to 12v   Please subscribe to my YouTube channel here:  https://www.youtube.com/c/EngMousaalkaabi?sub_confirmation=1

This circuit is a high voltage PWM dimmer for DC load. it can be very useful because most dimmers that available in markets are 12 to 24v. I tested it by 33v(because my power supply can't give more voltage)  but it can work by up to 50v DC. R2 can be 1k to 1.5k. Parts list: IC 555 N-Channel MOSFET such as IRFZ44 Diode 1N4148 Zener diode 10v 1W Potentiometer 50k Capacitor 0.1uF Resistor 1k(2pcs) As you can see in following fig. there are some parallel horizontal lines in image when you see to a PWM LED from an camera because it flashing with very high speed, that also occur when you want to take a picture from CRT TV display.

PWM today used in many areas such as solar charger, motor speed controller, light dimmer, mobile battery charger, etc. Following circuit is a PWM light dimmer that used IC 555. By this circuit you can change the brightness of LED lights. It also help to decreasing power consumption because when the LED is ON in fact it flashing by very high speed but the humans eye can not identifies that so we will see it continuous shine.