Over years we have published a handful of voltage regulator circuits in this website – which serve many purposes. In this article I am compiling a quick list of the best voltage regulator circuits that will be useful for all of you. The term “Voltage Regulator” is some what general in nature – it can be an AC-AC regulator or a DC-DC regulator. Basically what it does is simple – it regulates and maintains a desired voltage level as constant at the output terminals. So let’s start to dig down our big list 🙂
This is an easy to build circuit using IC 7806 (which is a 3 terminal positive voltage regulator). The circuit is designed such a way that 230 volts mains is step down to 9 volts using a transformer and is then regulated to 6 volts output. This IC is a stable one with internal current limiting and thermal shut down. It can give more than 1 A current output, if proper heat sink is used.
Linear voltage regulators are power inefficient as they dissipate lots of power in the form of heat. To solve such power efficiency problems, we can use a switching regulator which can save up to 85% of power compared to a linear regulator. Here we have a circuit using LM317 IC – which is a switching voltage regulator and it can deliver upto 3 Amperes of current. The switching regulator operates by taking small bits of energy from the input voltage source and then transferring it to the output with the help of a solid state switch and a control circuitry.
So here comes yet another simple voltage regulator circuit that uses IC 7809 to regulate an input of 16 volts. The 230 volts mains is stepped down using transformer and is then converted to 16 volts DC using a bridge and then it is regulated using the IC. As you know 7809 is a reliable IC with internal current limiting, thermal shut down and safe operation area etc.
Well, this is a collection of voltage regulator circuits using the LM317 IC – which is an adjustable voltage regulator. LM317 is a three terminal adjustable regulator from National semiconductors and it’s input can range up to 40 volts. The output voltage can be adjusted from 1.2 V to 37 V. Now this article is a collection of 4 circuits using LM317.
1. A general positive voltage regulator – The output voltage can be adjusted by varying the pot and resistor. There is an equation given to calculate V0ut.
2. Adjustable voltage regulator circuit – where the output voltage can be selected digitally. This circuit is nothing but a simple modification of the conventional voltage regulator circuit using LM317. Here instead of a pot, 4 resistors are connected in parallel which are activated only by the associated transistors. Thus each transistor acts as a logic level and is turned on or kept off. By selecting transistors and turning it ON – output voltage level can be adjusted.
3. 5 Ampere constant current/ constant voltage regulator – You got it from the name rite? Compared to above circuits this one is a little heavy and has got more components. It uses an LM310 operational amplifier along with LM317.
4. Power follower circuit – got confused what it is? None other than a voltage follower with high current capability.
This is an easy to make DC to DC voltage regulator circuit using the reliable MSK5012 IC. The output voltage can be programmed using the two resistors R1 and R2. The specialty of this IC is low drop out voltage because of the use of MOSFET as internal series pass element. The MS5012 has a high level of accuracy and ripple rejection.
So here is a really powerful 12 Volt regulator using IC 7812 which can deliver upto 15 Amperes of current. The 7812 regulator is used to maintain output at 12 volts and three TIP 2599 transistors are used to boost current. This is a costly circuit because of the high power components used. So assemble only if you are in need of one.
So here comes the first zener controlled voltage regulator. So this circuit is a really simple and easy to assemble type using a Zener and a series pass transistor (2N3055). It can deliver an output current upto 3 Amperes. When you use zener diode as voltage regulator, theoretically you will get 0.7 volts less at output. In this case – 11.3 volts.
Voltage regulator using LM723 IC – which is linear regulator from National semiconductors. The input can be upto 40 volts and it’s output can be adjusted from 2 volts to 37 volts. Without any adjustments, the IC can deliver upto 150mA current and further improvements in current can be attained by adding a series pass transistor – in our case MJ3001 a Darlington transistor.
LM338 IC is made from the house of ST Microelectronics. The IC has time dependent current limiting, thermal regulation and is available in 3 lead transistor package. The LM338 has an output voltage range between 1.2V and 30V and it can deliver output current well over 5 Ampere. R1 and R2 is adjusted to program the desired output voltage.
Hmm!! This is the most simple voltage regulator circuit diagram in our website! Just got an IC LM117 and 4 passive components. You can adjust the output voltage by varying the pot. LM117 is a reliable IC which can output regulated voltage in the range of 1.2 volts to 37 volts. This power supply can provide current upto o.5 ampere.
This article is more of an educational purpose than your practical needs. Switching regulation is different in concept compared to linear voltage regulation. The main advantage of a switching regulator is power efficiency. This article is pretty good enough and it will take you through theoretical aspects of switching regulation, simple switching circuits, some practical applications of switching regulators. Towards the end you will find an explanation linear regulation v/s switching regulation. I highly recommend you this article for your knowledge boosting.
LM350K IC has features like thermal regulation, short circuit protection etc. This is an easy to assemble circuit and is found to have better ripple rejection and stability compared to the elementary voltage regulator using LM350 IC.Output voltage can be adjusted from 1.2 volts to 25 volts by varying POT R2. We can get upto 3 amperes of current from this circuit application.
Here comes the first boost converter circuit using IC LM2698 (from National semiconductors). LM2698 is a general purpose boost converter with outputs ranging from outputs ranging from 2.2V to 17V DC. In this specific circuit you can get 12 volts DC output from 4.5 to 5 volts DC as input source.
Another simple circuit using monolithic integrated adjustable voltage regulator IC L200. This IC has features like current limiting, thermal shut down, power limiting, input over voltage protection etc. Resistors R1 and R2 must be adjusted to get the desired output voltage. We can get an output of 2.8 volts to 15 volts at 1 Ampere current.