Regulated bench power supply is one of the important tool in electronics. But it is very expensive. so today iam going to show you to make cheap variable work bench power supply. You can use it to power your prototype modeIs. And i designed it to supply from 18 volt to 3.3volt of DC and maxmium current of 1.5 Amps. You also Change as per your requirement.

## Step 2: COMPONENTS REQUIRED

* Transformer (step down from 230 v to 24 v Ac)
* Diodes
* Capacitors (1000uf, 10uf)
* LED'S
* Resistors (check circuit for values)
* Buck Sticks( male & female)
* Resistors (see circuit for values)
* Voltage regulators (7805, 7809, 7812, 7818)
* Battery clips
* Heat Sink Tube
* PCB Board
* AMS 1117 3.3V (This is 3.3 volt regulator i extracted it from old Arduino Board)

## Step 3: TOOLS REQUIRED

* Soldering Iron
* Soldering Paste
* Write Cutter
* Tweezers
* Multimeter

## Step 4: CIRCUIT

Here the Circuit for our project. Check The Values of Components to get the accurate Output.
( Check that 3.3 volt regulator is connected from 5 Volt Regulator Don't connect it Directly to the rectifier).

## Step 5: Electronics and Soldering

Before Starting The Project You Need Some Basic Electronics Skill and Soldering Skill. Or you will struggle a lot.

## Step 6: Theory

We aren't going to get into the heavy detail of the electromagnetic theory behind transformers except to say that the voltage stepped down using the step down transformer for current check the transformer rating. Then the voltage is converted into DC using the full wave bridge rectifier. But the rectified output have some Voltage Ripples. It can be overcomed by using the filters. The filters in the circuit smooth voltage. Then the voltage is regulated by using the voltage regulator.

## Step 7: DC Voltages

You get the stepped voltages of 18 v, 12 v, 09 v, 05 v, 3.3 v. I used shunt connector to change the voltages simply by swapping it. you can also use switch to change the voltages. Finally this is useful for powering and checking the prototype models. But the drawback of this converter is it used for only low power devices. For high power you need Buck-Boost converter.