mousa

Relay coil after switch ON needs to voltage much lower than its nominal voltage,  We can use this property of relay to saving 85% of the power to increase the battery life in battery powered circuits. To reduce the current / power consumption we can put a resistor through the relay coil, but since this low current not enough to running the relay at the beginning so we should short out the resistor for 1 second, then the relay switch keep going.  You have to use this formula to calculate the suitable resistor value: For more explanations please watch this video:   

Electronic load using Op-Amp IC 358 In this circuit i using IC 358 and some few components to make a simple constant load.  The trick here is connecting a dc voltmeter to the non-inverting input of the op-amp to preset the current before connect it to the battery or the super cap. under test. For more explanation you can watch the video below. Parts list: LM358 : https://www.banggood.com/custlink/Dvv3hO51Df High power resistor: https://www.banggood.com/custlink/K3GvYjHwRm Digital DC Voltmeter: https://www.banggood.com/custlink/3vmDYL5TDU Copper board: https://www.banggood.com/custlink/3KDDmMsPSc MOSFET IRFZ44N : https://goo.gl/35n5Tb   Potentiometer 100K : https://goo.gl/dKnWCj Resistor kit (10 Ohm): https://goo.gl/TgSaff Heatsink: https://www.banggood.com/custlink/D3KGdOSmzf   Circuit:   Gerber file: Download the Gerber file from here:  https://drive.google.com/open?id=1Lx8xjfkyYPvvzAbA0ponFBYBTQDqrMvU Video: For more explanation you can watch the video below...

Educational Logic gate PCB by PCBWay.com This PCB project designed to learning students how logic gates works The circuit used 4 ICs to simulation 8 basic logic gates (AND-NAND-OR-NOR-NOT-XOR-XNOR-Buffer)  You can order this PCB from here: https://www.pcbway.com/project/shareproject/Educational_logic_gates_PCB.html Get 10 PCBs for Only $5 (First Order Completely Free) https://www.pcbway.com PCBWay is a chines PCB manufacture which make PCBs with high quality and low price Parts list: IC 4011 IC 4081 IC 4071 IC 4030 or 4070 LED Green (8pcs) LED Red (14pcs) IC Socket 14dip (4pcs) C1 Capacitor 220uF 10V C2 Capacitor 100nF R1 to R15 (except R5) Resistor 10K (14pcs)  R5-R16-R15 Resistor270R (3pcb) Push button switch (14pcs) Micro USB socket Circuit diagrams: There are 100nF and 220uF Capacitor between VCC and GND Download the Gerber file here: https://drive.google.com/open?id=1267Jn87LuZV3SvwyiM09YhhPc2et9mCZ Video:

Using ultrasonic sensor without arduino Parts list: IC 555 IC KA2284 LED(5pcs) Ultrasonic receiver & transmitter Resistor 1K Resistor 2.2K Resistor 10K Resistor 100 ohm Potentiometer 10K (2pcs) Capacitor 10uF (4pcs) Capacitor 3.3nF Transistor 2N2222 Buzzer There are 2 ways to using Ultrasonic sensor without microcontroller: First way, the buzzer turns ON when you put your hand near the sensor   Second way the LED bar show you the distance level between the sensor and the objects. Video: More information in the video

Photocell or auto dark activated switch using for running garden or street lights in the night and turns them OFF at the day time automatically so it helps to power saving. The traditional photocell has two problems: 1-Standby power loss (around 1.6W) 2-Has 3 wires which is difficult to install I designed and make a new circuit that haven't those two problems. Parts list: IC 4093 SCR c106m LDR Bridge diode 4A Resistor 1M Resistor 30K Zener diode 9.1V 1/4W Circuit diagram: Important notes: 1- For this circuit you can only use SCR with sensitive gates such as BT169 or C106M 2- The IC used in this circuit is 4093 because it is micro-power IC , you can't use other NAND or NOT gate ICs.  3- Max. Load this circuit can handle is depend on SCR and bridge diode. The circuit can handle about 4A if used SCR C106M and 4A Bridge diode. 4- This circuit deal with 110/220V AC so can be very dangerous if you touch any component in the circuit. Video:

Traffic light using 4017 and 555 Parts List: IC555 IC4017 Transistor 2N2222 or any other NPN(3pcs) Red 3mm LED(35pcs) Yellow 3mm LED(35pcs) Green 3mm LED(35pcs) Potentiometer 1M Resistor 100K Resistor 200R 1W Resistor 1K(3pcs) Capacitor 10uF 16v Diode 1N4007 or 1N4148 (9pcs) Circuit: Note:  Use 3mm LEDs only Gerber File: https://drive.google.com/open?id=148pt9TWYS_L4lGvcN-ootc40P0dDy-2m Video:

This circuit is an LED Chaser with 81 LEDs using two 4017 ICs and 555 timer The circuit explained in this video here: https://www.youtube.com/watch?v=JoBsPduHEyc PCBWay is the sponsor of this project Website:  www.pcbway.com You can download the Gerber file or reorder this PCB here Circuit diagram: Parts list: IC 4017(2pcs) IC 555 5mm LEDs (81 pcs) 1K resistor(9pcs) 10K resitor 3.3K resistor 470R resistor 2N2222 transistor(9pcs) 1uF capacitor 100K potentiometer 1N4007 diode Video:

LED Chaser/Sequencer using IC 4017 & IC 555 Parts list: IC 4017 IC 555 LEDs (22pcs) Diode 1N4007 (10pcs) Potentiometer 100K Resistor 330 ohm Capacitor 2.2uF 16V I connect two LEDs in parallel to each output. The Diode through positive supply (VCC) used only for reverse polarity protection(not necessary).

81 LED Matrix X-Y controlled with two Clock pulses (different frequency) using 4017 IC Parts list: 4017(2pcs) LED (81 pcs) Resistor 330R (9pcs) Resistor 10K (9pcs) Transistor 2N3904 (9pcs) Circuit: Video: 

220V AC Dimmer using Arduino and making PCB order from JLCPCB  Wiring: Convert to PCB using EasyEDA: PCB order on JLCPCB.COM: Parts list: Arduino Nano Triac driver MOC3021 Optocoupler  PC817 Resistor 100K (2pcs) Resistor 470R (2pcs) Resistor 100R 1W Resistor 330R Resistor 10K Capacitor 100nF 400V 7Segment (Common cathode) Triac BT136 Diode bridge 0.5A IR receiver 1838B Terminal connector 2Pin (2pcs)  Push-button switch (2pcs) Download my Gerber File from here: https://drive.google.com/open?id=1DStmUIO0fcXJRmCG-zzzemJQBiqQ22zv Video:  Code: #include "IRremote.h" //-----( Declare Constants )----- int receiver = 9; //-----( Declare objects )----- IRrecv irrecv(receiver);           // create instance of 'irrecv' decode_results results;            // create instance of 'decode_results' //-----( Declare Variables )----- #include <TimerOne.h>   ...

High voltage probe for multimeter

Many people forgets the bathroom and toilet lamps in ON state, absolutely this causes increasing electric bill and even decrease lamps lifespan. This circuit is a simple way to turning ON and OFF the bathroom or toilet lamp automatically without using microcontroller. The circuit based on the counter IC4017 and laser. when a person go to bathroom his body cut the laser ray that is focused on the LDR in another side of the door frame, connecting and disconnecting the laser ray changed the LDR electric resistance and giving a positive signal to pin14 of the IC4017 through transistor 2N2222, since pin4 jumped to reset pin (pin15) so the output selector will be changed between pin3 and pin2. Pin3 run the transistor to running the relay. Two LEDs showing ON state and OFF state. 330 ohm resistor used to LEDs protection by giving 15mA current to them. You can use any other NPN transistor rather than 2N2222 such as BC547, C9013, 2N5551, etc.  This circuit is suitable for light switching fo...

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