Simple 1N4007 Diode Darkness Sensor Circuit

Here I made a simple Darkness sensor circuit using a Diode. Every Diode is mainly made up of P-type and N-type semiconductors.

These semiconductors are secured in a Black casing. This is because light from outside will create obstacles to the Diode’s main works.

Here I removed the protective cover of the Diode and exposed it with direct light and I found there is a continuity going on to the circuit.

So, I used these specific characteristics to make a simple Darkness sensor.


  • 1N4007 Diode
  • BC547 Transistor
  • 3.7v Li-ion Battery
  • 1S Battery Holder
  • 1M Resistor

Circuit Schematics:

There is the simplified diagram made through EasyEDA.

How does the 4007 Simple Light Sensor work?

For sensing the light we generally use LDR also known as the light-dependent resistor. This is like a special type of resistor which can change its resistor value according to the light intensity. So it means that when the intensity of the light is high then the resistor value will be lower and when the intensity of the light is low then the resistor value will be infinite. 

 I have found nearly the same characteristics in a general-purpose diode. That’s why I just broke a diode shell and I find there are two conductors inside In it. They are P and N-type Semiconductors. The semiconductors and mainly doped with Silicon. So when we expose the internal material of the diode then the diode becomes conductive and able to flow current through it. 

In the same principle, I made the circuit if you see the circuit diagram carefully you can see the diode is connected in Reverse Bias. So it means that it will not flow any current from Vcc to the ground without any modification. 

So now the current flowing path is from Vcc to the Q2’s Base and now this signal is very small so it will not able to run the LED. That’s why we need to amplify the signal for using it. So, here it comes the Q2’s emitter pin is connected to Q1’s Base Pin so now this signal is amplified. This amplifier signal is now able to run or drive the LED. 

 This is a simple case. After when we modify the diode we can see when we give light to the diode then the LED will off 

Here is why…

When we give light to the diode then it became conductive. so we all know that the current flows from the shortest path. so the current will flow from Vcc to the ground through the 1M resistor and the diode. No current will flow into the Q2’s base. So it will not activate the Q2 as well as the Q1 and the LED will not run. 

Watch Youtube Video:


The main point is the diode is not that much light sensitive. So we will need a high intensity of light for running this circuit. Here I used a phone flash which has a high intensity of light. So this works just fine. 

Attiny13a IR Remote Control

Today in this article we are going to discuss how to make an IR remote controller with an Attiny microcontroller. We can use any microcontroller for this project but for low being low complexity and making the circuit as small as possible we are using an AtTiny13a Microcontroller. But you can also use any popular microcontroller board like Arduino UNO, Arduino NANO as your wish. Both will work just fine.

Components for the Circuit:

  • Push Button – 5
  • ATTiny 13 IC – 1
  • 100R Resistor – 1
  • 1k Resistor – 1
  • 0.1uF Capacitor – 1
  • 2 Pin Screw Terminal Block – 1
  • 3.7v Battery – 1
  • PCB – 1
  • 5MM LED – 2
  • IR LED – 1

Tools Required:

  • Soldering Iron 60W Recommended
  • Soldering Stand
  • PCB Stand
  • Soldering Iron Fine Tip.
  • Tip Cleaner
  • Pliers
  • Jigsaw.
  • Flux
  • PCB Holder.

Circuit Diagram:

I designed the Schematics in online through Easyeda Website.

How Does the Microcontroller-based remote control works?

Every Remote has an integrated chip inside it. When any company makes Any smart device then they just give a hex code to the program IC.  So, first, we have to identify the hex code.  And it is very simple by using the given code in the  Arduino example code. Then we will map the values to the ATtiny Micro-controller Pins. In this simple way, we can map any necessary switch and make the smallest remote.

PCB Making:

I made the schematics. Then I ordered it from PCB from JLCPCB. Their work is professional. PCB looks Promising and can ship to your doorstep within a week. I have to say their customer service is superior. So, I prefer JLCPCB from Other PCB Manufacturers. You can also order from them.

Top Silk Layer Preview:

Here is the Top Silk Layer preview of the PCB. 5 Switches are used in this Circuit for different functions.

PCB Layout:

Here is the Top Layer and the Bottom Layer of the PCB. You can use this pictures to make the PCB in home through your Printer. And with some PCB Aching process you can make the PCB at home.

PCB Bottom

PCB File:

Here is the PCB Gerber file Link:

TL494 100W Inverter Circuit

Today in this article we are going to make a 100W Inverter circuit with TL494 PWM IC. The main function of the IC is to create variable PWM Pulses for different applications. Now for making the Inverter we have to make a 50Hz signal ( By calculating PWM Pulses). We will use a couple of other complimentary components for making the Inverter possible. The components are Some Resistors and a capacitor.

If we check the IC Datasheet then we will find some Important equations to calculate the important parameters of the IC. Sometimes it is also not possible to get the exact value of the components. Then our motive will be to find the components which have the nearest value.

Components for the Circuit:

  • TL494 IC – 1
  • IRFZ44N MOSFET – 2
  • 220R Resistor – 2
  • 2.2k Resistor – 1
  • 4.7uF Capacitor – 1
  • 2 Pin Screw Terminal Block – 1
  • 3 Pin Screw Terminal Block – 1
  • 12v Battery Connector – 2
  • 12v Battery – 1
  • MDF Sheet (8MM) – 1
  • 10MM Wood Screws – 20
  • 5 Pin Socket – 1
  • 220v to 12v-0-12v Transformer – 1

Tools Required:

  • 60W Soldering Iron
  • Soldering Iron Fine Tip.
  • Soldering Iron Tip Cleaner
  • Pliers
  • Jigsaw.
  • Drill Machine.
  • Different Drill Bits.
  • Glue Gun
  • Flux
  • PCB Holder.

Circuit Diagram:

The P1 terminal block is used for sending the 12V DC Power and The J13 terminal is for giving the 12V Input to the circuit. For the Mosfets, you can use an N-channel MOSFET as your wish. I had the IRFZ44n Mosfet lying around so I used that. You can also use IRF3205 as well.

How does the TL494 Inverter work?

This is the simplified diagram for the 100W Inverter Project. R1 and R2 are the Gate resistors for the MOSFETs. this protects the MOSFET from over-voltage damage. The voltage that is needed to operate the MOSFET will be provided by the Gate resistor. So, The gate resistor is a very important component.

Now for generating the 50Hz signal we only need 2 basic components. One Capacitor couple with a resistor. And the P1 Terminal block is for sending the squire wave pulses to the Transformer Primary coil. Now from the Transformer secondary coil, we will get the 220V Output.

PCB Making:

I made the schematics and the PCB. Then I ordered it from PCB manufacturer JLCPCB. They are professional at their work. PCB looks Promising and can ship to your doorstep within a week. I have to say their customer service is superior. So, I prefer JLCPCB from Other PCB Manufacturers. You can also order PCB from JLCPCB with the following Gerber file.

PCB Layout:

Fabrication File:

PCB Gerber file link

Watch Inverter Tutorial Video:

Simple 5W Audio Amplifier Circuit with C1815 NPN Transistor

How to Make a Simple 5W Audio Amplifier Circuit with C1815 NPN Transistor?

C1815 is a BJT Type NPN Transistor. Generally, the NPN Transistors are mainly used for Switching, Amplification. This example circuit is a basic example of Transistor Amplification. Not only C1815 but also you can also use any NPN Transistor you have lying around. The Amplifier output power may differ according to the Transistor rating. Here we will get a maximum of 5W output from the amplifier. For a general user, 5W Speaker is more then enough else if he is a heavy music lover.

Amplifier Working:

Every audio signal is more likely an oscillation. The amplitude of this oscillated signal is low when it is generated. Mainly we find this type of signal in Mobile Phones, laptops, and other media devices outputs. More likely this signal is suitable for driving small earphones headphones. Here we will increase the amplitude of the media signal and then connect it with a speaker for listening to the loud sound.

Components Needed:

  • C1815 NPN Transistor – 1
  • 10k Resistor – 1
  • 100uF Capacitor – 1
  • Small 5W Speaker – 1
  • 3.5mm Audio Jack – 1
  • 9V Battery – 1

Tools Used:

  • Soldering Iron
  • Soldering Paste
  • Nose Pliers
  • Wire Cutter
  • Breadboard

Circuit Diagram:

I designed the circuit schematics diagram on free online software EasyEDA.

How to Make it?

First, gather all the components as I mentioned earlier. Now attach all the components step by step. First, connect the Transistor’s collector and base with a 10k Resistor. Now take the 100uF capacitor and connect it’s -ve with. For the audio transmission, we will need a jack. Here I am using an old 3.5MM Jack from an old Headphone. You can also get this jack from online in a couple of bucks.

The circuit is ready to give power to the transistor. It is recommended to use any voltage between 5 to 12V. In the next run, a song from your media device and you are good to go. Now you can enjoy your shooting pleasant music with high volume.

PCB Layout:

PCB Fabrication File:

Here is the Gerber file for the PCB if you want to replicate the same thing.

Making Video:

This is the Video from Creative Creator that will help you to replicate the amplifier. Make Sure you Subscribe to our channel.


Lastly, I would say this is an easy circuit for electronics enthusiasts for making something new. If you are a beginner then you should definitely try making this and maybe you can make your first Boom Box with it. This is a Basic BJT NPN amplifier so it means that you can also use a more powerful amplifier with a more powerful transistor.