How to Make a Bench Power Supply
Mar 31, · 1. Add a zener diode and a resistor to your circuit to create a 5V power source and stabilize the voltage even more. Add a V zener diode (we used a 1NA) in series with a resistor, R_zener (we used a 68 ? and ? resistor in series). These two components should be added in parallel with the µF capacitor. Jul 06, · How to Make a Bench Power Supply Step 1: Tools and Parts Required. Step 2: Basic Block Diagram. Before heading in to the making process, you should know the basic components of a Linear Step 3: Transformer. Input high voltage AC going into a transformer which usually steps down the high voltage.
Have you ever needed a 12 volt power supply that can supply maximum 1 amp? But trying to buy one from the store is a little too expensive? Well, you can make a 12 volt power supply very cheaply and easily! I needed a 12 volt power supply for my project, the SSTC Solid State Tesla Coiland also made this instructable because it might be use full to someone If you want a 5 volt power supply, just simply replace the LM to a LM regulator.
Datasheet for LM78XX If you are going to pull out about 1 amp from this power supply, you will need a heatsink for the regulator, otherwise it will generate very high temperatures and possibly burn out However, if you are just going to pull out a few hundred milliamps lower than mA from it, you won't how to create power supply a heatsink for the regulator, but it may get a little bit warm.
Also, heres the schematic I also add in an LED to make sure the power supply is working. You can add in an LED if you want. Well, read the schematic and build the power supply! If you don't know how to read schematics, you might want to look here. Make sure you get good solder joints and no solder bridges, otherwise your power supply won't work!
Oh, If you don't know how to solder, read this great instructable! How to solder! After you had built what does core value means power supply, test it with your multimeter to make sure they are no solder bridges.
After you tested it, put it in a plastic box or something to protect you from shocks. But do not operate the power supply like I did, it is very dangerous because of the mains voltage on the transformer, you or somebody will get badly what are some effects of industrialization My power supply has You had built a cheap power supply!
You can use it for what ever your needs But again do not operate it without any protection! If you need any help, or questions, or any thing, make a comment! Question 5 days ago on Step 6. Hi there, I had a look at the datasheets for the LM34XX series chips and I am wondering why the values of the caps in your circuit differ from those shown on the data sheet.
I what is the best open source ecommerce solution because the supply on the datasheet is assumed "pure"DC and you have added smoothing caps for the rectified output from the diode bridge? Question 1 year ago. Question 2 years ago on Introduction. Or I'm I totally bananas over here :S?
Question 2 years ago on Step 6. Could you go into some detail about what materials they are made out of and why? Thank you! Question 2 years ago on Step 3.
This is a really big help. Could I please get the complete diagram of the schematic? I wish to use this circuit for learning purpose. If i use a transformer of 2A, how much current will be generated after making supply to 12volts?
Reply 3 years ago. Ok thanx for this but you didn't mentioned Capacitor How to create power supply. Plz let me know which voltage of capacitor i use. Since this is a 12v circuit, you may use 24v capacitor. Capacitor voltages are usually calculated as twice as the circuit voltage. Hello everyone One of the most used electronic circuitry is its many applications The simplicity of the electronic circuit is a good job 12 volt circuit.
Sounds like a good project. However, I am wondering how steady the output of the power supply is. I am in need of a small power supply of this voltage for an audio project, and given the application I need a fairly steady DC waveform with minimal ripples.
Would this supply work for that? Where did I should put the resistor? By Plasmana Follow. More by the author:. About: ——————————————————————— "Energy cannot be created nor destroyed… More About Plasmana ». Things that you will need to make this power supply is Piece of veroboard Four 1N diodes LM regulator Transformer that has an output of 14v - 35v AC with an output current between mA to 1A, depending how much power you will need.
I found a 16v mA transformer in a broken alarm clock. Also you will need the tools to make this power supply Soldering iron Wire cutters Wire strippers A thing you can cut veroboard tracks. How to setup dual monitors on windows 10 glue To hold components down and make the power supply physically strong and sturdy.
And some other tools that you might find helpful. Okay, I think that is about it, lets get to work! Did you make this project? Share it with us! I Made It! MatthewM Question 5 days ago on Step 6. Answer Upvote. How would I go about modifying this design so that it would only put out 1 milliamp? Reply Upvote. You should probably add a heat sink to the voltage regulator just to be safe. AllanT43 Question 2 years ago on Introduction. Another 2 way desing sir it is okay to use this on a booster amplifier??
Wickstrom Question 2 years ago on Step 6. JenorbinC 2 years ago on Introduction. Rajdeep Barman 2 years ago. Naveedm15 3 years ago. NeerajM27 4 years ago.
Step 1: Build a Basic Full-wave Bridge Rectifier
Mar 07, · There are more efficient and complex power supplies in the world. There are easier ways to get a simple power supply like this one (re-using a wall-wart, for instance). But if you make a power. May 31, · Yes transformer is the main part of power supply. we also use transformer. and additional components we use diode bridge for ac to dc converter. only transformer cannot provide us dc supply. we must use other components for convert it in DC power.
A bench power supply is an extremely handy bit of kit to have around for electronics hobbyists, but they can be expensive when purchased from the market. In this Instructable, I will show you, how to make a variable lab bench power supply with a limited budget. It is a great DIY project for beginners as well as any one interested in Electronics. The main objective of the project is to learn how a linear power supply unit works. This is a high quality stabilized voltage supply with which the voltage can be regulated continuously, and the range in which to regulate the voltage is V.
It even contains a current limit circuit which can effectively control the output current from 2mA to 3A with the ability to regulate the current continuously, and this unique feature makes this device an indispensably powerful tool in the circuit lab.
Before heading in to the making process, you should know the basic components of a Linear Power Supply. Transformer: The transformer changes the ac mains voltage to a desired value. It is used to step down the voltage. This also serves to isolate the power supply from the mains input for safety. The bridge rectifier converts AC into DC.
But this is not we want, we want a pure ripple free DC waveform. The filter circuit is used for smoothing out the ac variations ripple from the rectified voltage. Large reservoir capacitors are used for this. Linear regulator: The output voltage or current will fluctuate when there is change in the input from ac mains or due to change in load current at the output of power supply.
This problem can be eliminated by using a voltage regulator. It will maintain the output constant even when changes at the input or any other changes occur. Input high voltage AC going into a transformer which usually steps down the high voltage AC from mains to low voltage AC required for our application. For designing the Power Supply,the transformer secondary voltage is selected by considering the the output voltage of the power supply, losses in the diode bridge and the linear regulator. A typical waveform of 24V transformer is shown above.
In general we allow about 2V - 3V drop for the bridge rectifier configuration. So the transformer secondary voltage can be calculated as below. The nearest voltage rating transformer available in the market is 24V. Note : The above calculation is a rough estimation to buy a transformer. For accurate calculation you have consider voltage drop across diodes,voltage drop of the regulator, ripple voltage and rectifier efficiency also.
The rectifier bridge convert an alternating voltage or current into corresponding direct Current DC quantity. The input to a rectifier is ac whereas its output is unidirectional pulsating DC. The voltage drop across a general purpose diode is around 0. At any instant two of the diodes in the rectifier bridge are in operation. But since the diode conducts heavily, it may effectively be higher. A good safe value is twice the standard or 0. The DC output after the bridge rectifier is approximately equal to the secondary voltage multiplied by 1.
The rectified voltage from the rectifier is a pulsating DC voltage having very high ripple content. The large ripples that exist in the output makes it almost impossible to be used in any powering application. Hence a filter is used. The most common filter is by using a large capacitor.
The output voltage or current will change or fluctuate when there is change in the input from ac mains or due to change in load current at the output of the regulated power supply or due to other factors like temperature changes. This problem can be eliminated by using a regulator IC or by a suitable circuitry consisting of few components. A regulator will maintain the output constant even when changes at the input or any other changes occur.
The LMT is an adjustable 3-terminal positive voltage regulator capable of supplying different DC voltage outputs other than the fixed voltage power supply.
The above example circuit uses a LM3 17 voltage regulator IC. The rectified output from the full wave bridge rectifier is fed to a LM regulator IC. By changing the value of potentiometer used in this circuit, the output voltage can be controlled easily.
Till now I have explained how a Linear Power Supply unit work. The AC voltage of the transformers secondary winding is rectified by the bridge formed by the four diodes D1-D4. The DC voltage taken across the output of the bridge is smoothed by the filter formed by the reservoir capacitor C1 and the resistor R1.
The circuit incorporates some unique features which make it quite different from other power supplies of its class. Instead of using a variable feedback arrangement to control the output voltage, our circuit uses a constant gain amplifier to provide the reference voltage necessary for its stable operation. The reference voltage is generated at the output of U1. The circuit operates as follows: The diode D8 is a 5.
The voltage in the output of U1 gradually increases till the diode D8 is turned on. When this happens the circuit stabilises and the Zener reference voltage 5. The current which flows through the non inverting input of the op-amp is negligible, therefore the same current flows through R5 and R6, and as the two resistors have the same value the voltage across the two of them in series will be exactly twice the voltage across each one.
Thus the voltage present at the output of the op-amp pin 6 of U1 is The trimmer RV1 and the resistor R10 are used for the adjustment of the output voltages limits so that it can be reduced to 0 V, despite any value tolerances of the other components in the circuit.
Another very important feature of the circuit, is the possibility to preset the maximum output current which can be drawn from the p. To make this possible the circuit detects the voltage drop across a resistor R7 which is connected in series with the load.
The IC responsible for this function of the circuit is U3. The inverting input of U3 is biased at 0 V via R At the same time the non inverting input of the same IC can be adjusted to any voltage by means of P2. Let us assume that for a given output of several volts, P2 is set so that the input of the IC is kept at 1 V.
If the load is increased the output voltage will be kept constant by the voltage amplifier section of the circuit and the presence of R7 in series with the output will have a negligible effect because of its low value and because of its location outside the feedback loop of the voltage control circuit. While the load is kept constant and the output voltage is not changed the circuit is stable.
If the load is increased so that the voltage drop across R7 is greater than 1 V, IC3 is forced into action and the circuit is shifted into the constant current mode. The output of U3 is coupled to the non inverting input of U2 by D9. U2 is responsible for the voltage control and as U3 is coupled to its input the latter can effectively override its function.
What happens is that the voltage across R7 is monitored and is not allowed to increase above the preset value 1 V in our example by reducing the output voltage of the circuit. This is in effect a means of maintaining the output current constant and is so accurate that it is possible to preset the current limit to as low as 2 mA. The capacitor C8 is there to increase the stability of the circuit.
Q3 is used to drive the LED whenever the current limiter is activated in order to provide a visual indication of the limiters operation. The same negative supply is also used for U3. As U1 is working under fixed conditions it can be run from the unregulated positive supply rail and the earth.
The negative supply rail is produced by a simple voltage pump circuit which is stabilised by means of R3 and D7. In order to avoid uncontrolled situations at shut-down there is a protection circuit built around Q1. As soon as the negative supply rail collapses Q1 removes all drive to the output stage. This in effect brings the output voltage to zero as soon as the AC is removed protecting the circuit and the appliances connected to its output.
During normal operation Q1 is kept off by means of R14 but when the negative supply rail collapses the transistor is turned on and brings the output of U2 low. The IC has internal protection and can not be damaged because of this effective short circuiting of its output. It is a great advantage in experimental work to be able to kill the output of a power supply without having to wait for the capacitors to discharge and there is also an added protection because the output of many stabilised power supplies tends to rise instantaneously at switch off with disastrous results.
Credit : This section is not written by me rather it is taken from electronics-lab. The full credit goes to the original author. Before stating the assembling of the kit read the Instruction manual carefully. The kit come with all the components mixed together in a single packet.
So, it is recommended start working by identifying the components and separating them in groups like : transistors,Opamps,Regulator,Potentiometers and the connectors. This really save a lot of time during the building of the kit. In the power supply kit, the highest number of components used are resistors of different values.
In the kit the resistors packed in a bunch and their values are not labeled. So we have to manually measure the resistance value by using a Digital Multi-meter. I measured the values and written on the small strip of paper in the resistor leg. The thumb rule for soldering the components on the PCB is " Solder the components according to their height". Always start with smaller height components. First I solder all the resistor,then diodes,then ceramic capacitors,then transistors then Opamps and so on.
Use a pliers when bending bridge diodes legs to avoid breaking. The metal part of the high power transistor 2SD and medium power transistor 2SD is attached to the heat sink, making it suitable for devices dissipating several watts of heat.
The heat sink for transistor 2SD is included in the kit. So you have to buy a separate heat sink for the other transistor 2SD But good thing is that the perfect size heat sink matching with the PCB outline and along with a Cooling fan is available from the same manufacturer.
You can buy it from Banggood. The potentiometer could be placed directly onto PCB, and could also be lined onto the board through its socket and wires.