IC 7805, 7812, 7824 Pinout Connection Explained

The post explains how to connect common 78XX voltage regulator ICs such as 7805, 7812, 7824 etc in an electronic circuit for getting the intended fixed regulated output voltages at 5V, 12V, and 24V depending on the selected 78XX specification

IC 7805, 7812, 7824 Pinout Specifications

Most of the common voltage regulator ICs beginning with the 78 prefix, such 7805, 7812, 7824 typically have identical pinout assignments as shown below:

complete datasheet of all voltage regulator ICs 7812, 7805, 78XX series

However, in the above chart, we can also see that except the 78LXX,  the other variants have slightly different pinout specifications, and needs to be connected exactly as per the given details otherwise the IC may fail to work and produce unexpected outcomes.

The ICs beginning with 78XX are positive voltage regulators, meaning these will accept a positive input voltage across across their input/Gnd terminals and regulate the same across their output/Gnd terminals with the specified fixed voltage output.

Conversely, the 79XX ICs will accept a negative voltage and produce a negative fixed voltage across their relevant output terminals.

The package of the ICs also signify a vital information. The ICs with TO220 package are rated to handle and produce a maximum of 1 Amp current whereas the smaller 78LXX version are rated to handle only upto 100mA.

How to Connect 7805, 7812, 7824 in an Electronic Circuit

We all very well know regarding the building procedures a DC power supply circuit using a transformer, a bridge rectifier and a filter capacitor.

It just requires connecting four diodes in a bridge configuration and connect it to the secondary of the transformer, the capacitor goes to the output of the bridge terminals.

The output produced across the capacitor is approximately equal to the rated voltage of the transformer, rather a few volts higher than the transformer spec.

However the voltage obtained from the above simple configuration is never regulated and stabilized, meaning the output from it will never be constant and will vary with the varying input mains voltage levels, which we know is never constant.

In order to regulate an existing supply to a fixed level, we normally use these 78XX ICs, and theses can be very easily connected with any supply source in the following shown manner:

 Application Circuit

application circuit for IC 7805, how to connect 7805

ICs 7812 and 7824 can be also connected exactly in the above shown manner, the only difference being the input/output voltage specifications which will vary as per the IC's ratings.

For example a 7812 will require an input above 13V and will produce a fixed 12V at its output.

Similarly a 7824 will require a input of not less than 26V, and will offer an output voltage fixed at 24V, and so on.

What does Capacitors do?

We can some capacitors attached across the input and output terminals of the ICs, these are just included to rectify any residual DC spikes and ripples that may exist in the supply line.

The value of these capacitors is not critical any value between 1uF and 100uF can be used for rectifying higher frequency ripples, whereas smaller capacitors in the range of 0.1uF to 0.47uF can also be attached in parallel to control any possible high frequency entry along the supply rails.

Importance of 78XX voltage regulator in circuits

A varying voltage can cause drastic consequences to a sensitive electronic circuit, for example a TTL, LS and HC series of ICs cannot tolerate more than 5 volts and can get immediately damaged.
A CMOS IC cannot stand more than 16 to 18 volts.

A relay if operated at voltages more than its rating can become hot and waste electricity unnecessarily.

There are several other issues which might be faced with electronic circuits if the applied is an unregulated one.

For solving the above issue, many high grade yet very simple to configure chips have been designed and are available cheaply and plentifully in our electronic markets.

The 78XX voltage regulator series for example, comes with most of the standard voltage ratings which can be used in conjunction with an ordinary power supply DC for obtaining high grade, clean voltage controlled outputs.

Technical specifications of the 78XX series IC

Output voltage tolerances are around ±2% at Tj
= 25˚C and ±4%
Line regulation is around 0.01% of VOUT/V of ∆VIN at 1A load
Internal circuitry is thermal and overload protected
Internal short-circuit current limit protections are also included
Output transistor safe area protection is also one of the features of these ICs

Identifying 7805/7812/7824 ICs Pinouts

A classic example can be seen in this article where a 7805 IC is used as a cell phone charger regulator.

Referring to the above circuit diagram

  • These ICs have just three leads, making it very easy to understand and connect. The leads are assigned as input, ground and output respectively.

  • Keeping the printed side toward you, the left side lead is the input, the center one is the ground and the right side lead is the output.

  • The DC from any standard power supply is applied across the input and the ground leads of the IC, the positive goes to the input while the negative is connected to the ground.

  • The output is acquired across the output and the ground pins of the IC, the positive being received from the "output" pin and the negative from the common ground line.

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abat said…
hi nice to read your article,everything is ok but only i couldn't any article about how to check the component with multimeter(analog/digital) especially the 78/79xx voltage regulator.And highly appreciation to you thanks you
Swagatam said…
hi thanks very much....these ICs cannot be checked with a multimeter....in fact no IC in this world can be checked using a multimeter, that's just not feasible.
smart faith said…
Hello sir, need a circuit diagram that convert from A.C(240-110) to D.C(5,9,12,24) volt without using transformer..,.thanks
Swagatam said…
hello smart, you can try this:

Shamriz Nahzat said…
Hello sir, need a circuit diagram that convert from D.C (12V 1A) to D.C(5V 20mA ) by using a voltage reglutor 7805.
Swagatam said…
Hello Shamriz, why do you need it to be 20mA.?..it can be be 1amp, that may not be an issue for your load.
jason paz said…
Hi sir. I have a 19v dc 6a source and want to convert it into a 12v battery charger. How can i do that using lm7812 ? I have a couple of 1N4001 diodes and couple of zener diodes, caps resistors. Any advice for a circuitry?
Swagatam said…
Hi Jason,

you can do it exactly in the manner shown in the first diagram of the following article:

Npa said…
Hello, i have a 7812 voltage regulator. Can i used it on 9v batterry? What is more suitable 7812 or 7805?!
Swagatam said…
what is your requirement? 9V with 7812 will give you 9V output and with 7805 it will give you 5V
james pinca said…
Hello sir U have any sample circuits of fixed voltage regulator using 7805?
Swagatam said…
hello james, you can refer to this article:

Avi Verma said…
I want the circuit diagram of internal circuit of ic7805 and ic7812
Raman Chaudhari said…
Dear Swagtham,

I want to use 0.5 watt 4.5 dc volt LED on 220/240 olt AC , please , give me circuit idea.
Swagatam said…
Dear Raman, you can try the following circuit


replace Z1 with 5V 1 watt zener diode and replace the 50 ohm resistor with 10 ohm 1 watt resistor
amarjit amarjit said…
Hello Mr. Swagatam I always read up right post. Please can u send me 10 to 20. 1watt led in series on 220v ac circuit.
Thanks in advance
Swagatam said…
Hello Amarjit, you can try the following universal concept


you can connect the LeDs in series at the output of the circuit, and use a zener diode having value equal to the total forward drop of the series LEDs.
Umair said…
Hello sir
I want to convert 130v1amp DC in to 12v8amp DC please help me
Swagatam said…
Hello Umair,

you will need a buck converter circuit for this...you can refer to this article

Parahlad said…
Hello sir
Can we use 7812 to take negative 12voltage from -24 volt
Swag said…
Hi Prahalad, sorry I am not very sure how to achieve it using a 7812 IC...
George said…
The circuit above is not correct as a 5V regulator cos the load voltage will vary depend on the IR drop across the 5ohm resistor. You need to leave the 5ohm out if you need a stiff 5V output.
Swag said…
The shown application is meant for charging a cellphone, that's why the 5 ohm resistor is included, the actual design can be be witnessed below:


for any other application the 5 ohm must be removed.

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