Make a Simple 12 Volt 1Amp Power Supply with transformer

Today we are going to make a 12 volt power supply that can supply maximum 1 amp with a simple transformer.

When we require a regulated 12V and 1Amp power supply it is little expensive when you buy it. But it is cheap & easy if you know the right recipe.

Items required:

Things that you require to make this awesome simple power supply are mentioned below:

(1)1N4001 diodes
(2)LM7812
(3)Regulator Transformer  having output of 14v - 35v AC with an output current between 100mA to 1A, depending on how much power you need.
(4)1000uF - 4700uF capacitor
(5)1uF capacitor
(6)Two 100nF capacitors
(7)Jumper wires (You can use simple plain wire as jumper wires)
(8)Heatsink (optional)

Circuit Diagram:

If you want a 5 volt power supply, just simply replace the LM7812 to a LM7805 regulator.

You can check the datasheet of the IC for ready reference.

For 1Amp we require heatsink for the regulator, otherwise it will generate too much heat and possibly will burn out.

However, if you require few hundred milliamps (lower than 500mA) then we don't need heatsink for the regulator. Although it will become slight warm.

Dear friends, simply build this amazing power supply and enjoy.

If you have any further questions please feel free to ask them in comment section,  I will try to answer them all.

Electronic mosquito repelent ultrasonic frequency generator circuit

Dear friends today we are going to learn how to make a circuit which act as mosquito repellent.

This circuit is very much easy to understand and use. A circuit with minimum components repel mosquito. Large number of things like coils, creams, oils is available in the market to repel mosquito. But these replant is also harmful for the humans . Oils and creams can led to skin disease, while coils or mats produces toxic fumes which can lead to breathing problem and lung cancer.

Our circuit do no harm for human being as it produces frequency which human being can not hear. Mosquito repellent generates a frequency ranges from 20-38 KHz. And mosquito runs away from your house as they irritates from these range of frequency.

Humans are only able to hear frequency which has a range from 20Hz to 20 KHz. All the rest frequency above this is considered as a ultrasonic frequency. Many animals and insects are able to hear this range of frequency. Usually in mosquitoes ultra sound is generated by the males and female one receives that one. While after breeding female mosquito usually used to avoid this frequency. And this circuit produces the same frequency as the male one generates, and these creates a stress on the antennae of the mosquito and these keep them away.

Here the basic principal of this circuit is to connect a such type of buzzer which can produce ultrasonic frequency range. With the help of oscillator in the circuit, buzzer is driven. And in the circuit oscillation is generated by 555 timer IC which is linked as a astablemultivibrator.

The circuit is connected in the closed mode and thus power is received by the 555 timer. In the starting stage voltage in the capacitor is zero volts.

So the voltage at the threshold `as well trigger pin is at zero volts. Now the capacitor starts charging via a resistor R1 and R2.There will be one point when the voltage of capacitor will be higher as compared to threshold voltage. At this stage capacitor starts discharging with the help of resistor R2, which is a discharging pin and it keeps of going downward till it reaches to its original state. Thus the signal at the output pin of IC will be an oscillating signal having 38 KHz frequency. With the help of pin 3 of timer IC 555 which is out pin of IC 38 KHz frequency drives to 38 kHz piexo buzzer. This buzzer will produce a ultrasound at a regular interval.

By altering the value of resistor R2 we can alter the output frequency.

By changing the value of resistor and capacitor, it can also use as an insect replier as insects are also able to hear ultrasound.
From the source ultrasound are transportable only at 45 degree. So in the situation when there is any hurdles in the track signals get diverted. Also it works on the place where population of mosquito are not much more.

Component Description:-

1. Power supply (12V)

2. Resistors (2.7kΩ x 2)

3. Capacitors (0.01µF x 2)

4. NE 555 timer

5. IC Diode (1N4007)

6. Piezo Buzzer

Working principle:-

(1) Here the 555 timer is configured in astable multivibrator mode , specifically devised for generating sound at the ultra frequency levels.

(2) The frequency of this circuit is set to 25 kHz, this frequency falls in the ultrasound region and it is not audible to human beings.
The 1N4007 diode is used to get 50% duty cycle for the frequency generator.

(3) The piezo buzzer converts the output of 555 astable to ultrasonic sound that can be heard by the insects.

(4) This ultrasound frequency cause some irritations and uneasiness to the insects such as mosquitoes. However it will not disturb you if you have installed this circuit of insect repellent for your home.

How to design this circuit:-

We need 25 kHz signal, so the time period will be 40µseconds .

Then T =T =20µSeconds .

use R= 2.7kΩ standard.

Simplest 5V Transformerless Power Supply Circuit

How to make Simplest Transformerless power supply for low current and low voltage application(5volt 150mAmp) using a IC-LR645

By:Alok kumar

Some of the followers of this blog have requested to post a simple low current and low voltage i.e 5volt & 100mAmp. So today i am going to post an transformerless power supply which is not only easy to construct but also very cheap and small or compact electronic circuit. This electronic circuit can be used to for various purpose like charging small li-ion batteries e.t.c. In this circuit we are going to use IC-LR645 which can control any voltage between 24 and 270 V AC and produces DC voltages below 15 volts at the output, which becomes ideally suitable for operating condition.

The great thing about this circuit is that it does not include or incorporate any bulky transformer but it also dont uses high voltage polar capacitors here. So no worries about surge current and we don't need crowbar protection circuit here.