Why use the 78xx voltage regulator? When our electronic projects need a fixed regulated DC power supply circuit.
For long times ago. I often use a Zener diode and transistor to build a regulator. They are good but has many parts.
So, now the first choice, we recommend using IC—integrated circuit in 78xx family.
It can be used the 5V, 6V, 9V, 10V, 12V, 15V, 18V, 24V at 1A fixed regulated power supply source.
It is easy to use, cheap, popular for a long time.
Parts used in this below circuits are easily available in most of the local markets.
For example circuits, use 78xx series in fixed positive voltage regualtors.
Suppose you are a beginner. All things in Electronics is too confusing. But you are interested in learning it. I used to be like you. I love learning through the circuit. When I watch a lot of circuits. I started to understand its system.
I try to design(draw) 9 example circuits for you. I hope you clear with these circuits.
78xx Power Supply circuits
We use voltage regulator IC-78XX series Or some call 7800 series. You can change Voltage output get follow want IC number!
- 5V uses IC-7805 (5V Voltage Regulator),
- 6V uses IC-7806
- 8V uses IC-7808
- 9V uses IC-7809
- 10V uses IC-7810
- 12V uses IC-7812
- 15V uses IC-7815
- 18V uses IC-7818
- 24V uses IC-7824
The load is typically regulated to within 10mV and no more than 50mV.
We still use PCB and other equipment as before. To use transformer 1-2A. IC-7800 series to Hold Heatsink.
5V Regulators using 7805
9V to 5V DC Converter Circuit
This is 5V portable power supply circuit for pic microcontroller experiments.
or PIC microcontroller power supply circuit.
As The PIC16F627A microcontroller use 5 volts DC power supply. My son need to build it as 5V portable power supply circuit, because of the need for safe and convenient use in all locations.
How it works
I want my son to embarked on building this projects by himself. So choose a simple circuit. as Figure 1. We use IC-7805 5 voltage DC regulator IC, which has been very popular.
We use the power supply input is 6 x 1.5V AA battery, Are connected in series The total voltage 9V. We used a conventional battery. It’s easy and cheap to buy.
Parts will you need
S1: switch to turn on-off this circuit.
F1: Fuse is used to protecting this circuit from overload output. We use 0.4A 50V only to safe all circuit.
IC1: convert an input voltage from 9V to 5V and the ability to maintain the regulated supply
LED1: for show power on
R1-resistor: reduce current flow to LED1 in safe value
C-100uF 16V-Electrolytic Capacitors: to filter current to smooth
C-10uF 16V-Electrolytic Capacitors: to filter output current to smooth
C-0.1uF 50V-Ceramic Capacitor: to reduce noise as ripple voltage on a high spike
Then I tech my son understand all components using on this project. As Figure 2 he draws them on his notebook.
Figure 2 all components that we use
How to builds
Next step He solder parts on DIY Prototype Paper PCB Universal Board as Figure 3
We tried to cut leg of parts with the nail of my wife. As it’s small, easy to use. And very cheap as Figure 4.
Then, we apply 9V power supply to the circuit, and measure voltage output is 4.95V it is ok.
Next, I assemble the circuit in the Box as Figure 5, it look is great, this step I help my son build it because it is hard for him.
He draw text on the box to clear to use.
Then, We test with the PIC16F627A circuit pic microcontroller experiments as Figure 6 it works well.
The parts we will need
IC1: IC-7805 5V DC regulator
C: 100uF 16V __Electrolytic capacitors
C: 10uF 16V___Electrolytic capacitors
C: 0.1uF 50V___Ceramic capacitors
LED1: LED as we like
R1: 470ohms 0.5W resistors
S1: ON-OFF switch
F1: Fuse 0.4A 50V
The Box, Wires, PCB, and more
Portable MP3 player Supply
This is a USB motorcycle power supply circuit. Motorbike repairman came to my house. Said, you know the story of how I like to build various electronics projects are always. And Talk to exchange knowledge with each other.
During this time, he had been installed the stereo in a motorcycle. Can turn to music Sound of reasonably good.
The regular budget, $ 50, depending on the speaker. (The bass -treble as you like) And small amplifier but high power (around 50 watts)
The source of music. He chose a portable MP3 player. Since there are several advantages as follows:
– small, easy to install.
– Battery built-in so not require an external power supply. When power is applied to charge it with the home AC power.
– Withstand vibration better
– Music store has hundreds of songs or more.
– To listen to FM radio.
Typically, he allows customers to buy into it. Since there are many to choose price under 20 $.
However, using this a portable MP3 player (an example Figure 1) It is not easy, because the battery runs out of power fast. Listening to music is not long or discontinuous, it must be removed to renew to charged.
Figure 1 The portable MP3 player
He had the idea to adapt draw power from the battery of the motorcycle used as a power supply of this portable MP3 player instead.
Based on such a problem, I see that is interesting so Thus volunteered to help him, by Appropriate focus on quality, ease of build. and saving budget (lower than 20$)
Figure out a way to match
He has further commented that the battery provide voltage of 12-volts. But this MP3 player use 5-volts power supply so must to have to the device to reduce voltage to 5-volts fixed. Because too much voltage may damage or permanently destroy the semiconductor chip in this MP3 player.
The current use he not tell me but I think do not many current because it use small LCD display and use one 1.5V battery only.
I think that the good device reduce voltage, is a steady 5V regulated power supply there. In In mind that use IC-7805 pay fixed voltage 5V 1A, Thus try to think of ways to make the design work, as Figure 2 appear to be more effective available.
The working principle.
We try to understand the circuit better. When connented the battery the current will flow through D1-diode by it serves to protect the connecting wrong polarity,is allow the positive only.
Also, while the 12-volts battery very weak, may be noise mix with voltage battery. But when has D1 will has new rectifier on positive voltage only that can get with them.
Then the current flow to C1. Which serves as filter to smooth. And The C2-capacitors acts reduce high noise frequency.
Then the input of IC1 and supply voltage of 5V regulated at output. By has C3 to filter voltage to smooth and has C4 reduce noise other on level.
Although IC1 would then overcurrent protection. But as a precaution. I insert F1-fuse protect over current of 0.5 A.
And I added ZD1 to protect over voltage., If the voltage exceeds 5.6V. Would be current flow through ZD1 lot. Makes F1 lacking in the end.
For LED1 to show the performance of circuit., If a 5-volts LED1 will light up. Except F1 lack or no power input. The R1-resistors connect to limited current of LED1 perfectly.
How to build
For the prototype. I assembled two sets him, both on the universal PCB board and on PCB as Figure 3 is Actual-size of Single-sided Copper PCB layout and has components layout as Figure 4 same generally projects.
You should wiring and components for errors. Rub pin devices, to help soldering easier, and leg positioning device correctly. In particular the electrolytic capacitors and diode.
Also, proper soldering with a soldering iron, no larger than 30 watts and use the lead for good.
Until success is a prototype based on Figure 5.
When soldering equipment and review their completed successfully. To take the 12-volts battery to enter in this circuit will see that LED show power on is indicated circuit works so well.
Then, try to take the portable MP3 player to the Motorbike as Figure 6 It turns out that a good result he let the fire is not left open several hours before this circuit that actually works. No problem
The parts you will need.
IC1: 7805 DC voltage regulator
D1: Diode 1N4007
ZD1: Zener diode 1N4007
LED1: LED as you need
C1: 1000uF 25V Electrolytic
C2, C4: 0.01uF 100V Mylar capacitors
C3: 100uF 25V Electrolyte
R1: 220 ohm 10K 0.25W -5%
Heat-sink 1 pcs.
PCB 1 pcs.
7806 DC Regulator 6V
The main parts of this circuit IC 7806. It is normal IC linear dc voltage regulator 6V at 1A current.
It is easy project electronic because used the minority part and low cost too.
I have of a 9Vac 1A transformer. The output of the transformer is rectified by diode 1N4001 or equivalent to more high power,
Thence to smoothed filter using 470uF 35V capacitors,so the volt this is unregulated DC voltage have value 11V-12V DC.
Besides must use this ic with a suitable heatsink.
Detail more, Please in image circuit.
8V 1A Regulator using 7808
If you want DC regulator 8V for your camera that use current about 800mA.
I recommend you try to use L7808 or LM7808 in TO-220.
Look at the photo below.
It is similar to other ICs in the 78xx series. The output current is 1A max and easy to use.
And Look 7808 Pinout here.
- The input voltage min 10VDC to 30V Max.
- Line Regulation: 0.25%
- Load Regulation: 0.25%
See in the circuit diagram below.
Here is 8V DC Regulated power supply circuit.
You should install a enough heatsink to it.
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