High Current Adjustable Power Supply Circuit using LM317

Variable power supplies are available in different ranges but they provide very low current of one or two amperes, they can’t drive high power devices like motor or high power lamps.

So to get through such problems I introduce a high current variable voltage power supply circuit which can drive 10A of load, the current handling capacity can be increased simply by connecting 2N3055 power transistors in parallel.

I happened to design variable power supply schematic diagram for my inverter battery for safe and quick charging. My 30Ah lead acid inverter battery takes more time for constant voltage charging when I use a LM317 variable voltage regulator. This is due to its lower output current.

So I connected a power transistor which helps to increase the current without varying the voltage. 2N3055 can handle 15A, so by connecting parallel make add the individual current.

This can be used as a regulated 48V DC power supply or 24 V DC power supply. The maximum input to this DC variable power supply is 37 volts.

Read More

How to Make a Simple Boost Converter with 555 Timer?

We may come across many circumstances where we need 12V from a 5V (as from USB ports which only provide 5V), but it may not be sufficient to drive all the circuits. To face such situations we are introducing a dc to dc boost converter circuit which can generate 12 volt from 5 volt. Today boost converter applications are used in different devices like dc dc power supply, dc-dc converter module, isolated dc dc converter etc. The main component used for this circuit is a 555 timer IC operating in astable mode. It generates a square pulse which is then given to a simple transistor inverter to get inverted outputs. These two outputs will drive a voltage pump which increases the voltage level by series addition. However this 555 timer boost converter has a disadvantage of low output current so it can’t drive high current devices. To get more current you have to use a step up converter circuit that we will introduce later.

Read More

Variable DC power supply schematic using LM317 voltage regulator

Variable voltage power supply is essential for any electronic hobbyist to begin their electronics lessons. For different applications you may need different voltages. So it becomes impossible to use multiple fixed power supplies all the time.

Also this variable power supply circuit ensures the protection of other circuit parts from voltage fluctuations. So in this article we will teach you how to build a variable power supply on your own. Why to buy when you can make one of your own easily using very little components?

Assemble this circuit on a PCB (Printed Circuit Board) and start your electronics projects. You can connect the output to a multimeter for displaying the voltage. 

Read More

Bridge rectifier regulated lab power supply circuit schematics

A good regulated AC to DC power supply circuit is essential for any electronic hobbyists and electronic students to do thier electronics hobby projects. Also a bridge rectifier power supply is one of the introductory circuits for beginners. Firstly we need to know what is a bridge rectifier? A rectifier circuit employs the conversion of AC voltage to DC voltage. Full wave bridge rectifiers have the benefit that they transfer both half cycle of AC input into DC output and also efficiency is two times greater than that of half wave rectifier. Bridge rectifier circuits are put into practice using diodes such as 1N4001, 1N4007 etc. 

• Transformer less AC to DC power supply
• Dual power supply using single battery source

Below is the circuit schematic of rectifier regulated power supply using 78XX voltage regulator IC. 78XX is a positive voltage regulator and available at different output voltages as 7805 for 5V, 7809 for 9V, 7815 for 15V etc. Hence you can implement power supplies for required voltages, that is 5V, 9V or 15V as you like. Solder this regulated power supply circuit on PCB and enclose it in a suitable case, definitely it will  help you for future circuit projects.

Read More

Transformer less AC to DC power supply circuit using dropping capacitor

Production of low voltage DC power supply from AC power is the most important problem faced by many electronics developers and hobbyists. The straight forward technique is the use of a step down transformer to reduce the 230 V or 110V AC to a preferred level of low voltage AC. But i-St@r comes with the most appropriate method to create a low cost power supply by avoiding the use of bulky transformer.Yes, you can construct power supply for your development without a transformer. This circuit is so simple and it uses a voltage dropping capacitor in series with the phase line. Transformer less power supply is also called as capacitor power supply. It can generate 5V, 6V, 12V 150mA from 230V or 110V AC by using appropriate zener diodes. See the design below.

Read More

Regulated dual power supply circuit from single battery source

How to create dual power supply unit using single battery for your lab prupose? Dual voltage power supplies are required particularly for op amp experiments and some of the instrumentation amplifiers. Some low power audio pre amplifiers also uses dual voltage supply. Here is a simple dual power supply schematic capable of producing +9V, 0V and -9V (dual polarity and ground potential) from a single 9V battery. You can create your own dual power supplies with different ranges of +Vcc and –Vcc such as +5V, 0V and -5V or +12V, 0V and -12V. This article gives the working and constructional details of the circuit schematic using single battery source.

Read More

Regulated voltage dual power supply circuit: +Vcc, –Vcc & Ground

Dual power supplies or dual power supply units are the most common equipment for an electronics hobbyist. It gives positive polarity, negative polarity and ground potential. Some Op Amps need dual power source that is +Vcc and –Vcc (Positive and Negative polarity). This article explains how to construct simple regulated dual power supply circuit with low cost components. It uses two types of voltage regulator ICs 7805 and 7905. 7805 is a positive voltage regulator where as 7905 is a negative voltage regulator IC. This dual voltage power supply definitely helps to develop your own DIY circuits.

Read More