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Ok, so we have a 230VAC (UK) power supply which goes onto a step-down transformer (230V to 15V), then we have a full bridge rectifier which creates a basic DC voltage, now to calculate the value of the capacitor I used the following formula:
C = (5 × Io) / (Vs × f)
5 = time constant
Lo = output current (I believe this is dependent on what we want to achieve with the circuit) Basically I took as an example 30mA (0.03A).
Vs = supply peak voltage (15Vrms * 1.4)
f = 50Hz (UK)
Now after doing the calculations I did get 158uF (1.58×10-4), is that correct?
Generally we use 10,000µF per Ampere of load as a rule of thumb.
If the capacitor is too small the ripple voltage kills them young
If the value is too high then the power factor is too poor, the transformer and diodes heats-up.
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Also how do I get +-5v from a bench power supply that gives +-12v and is not variable. Can I just use a simple voltage divider made up of resistors?
Can I use my mobile battery charger that has a rating for 5v and 350mA to drive my PIC microcontroller circuit. if the cirucit connected to the phone charger takes less than 350mA its alright isn't it, what will happen if it takes more?
You can't, not easily. yes, you can use voltage dividers, you need two. but either they don't regulate very well, if the resistor values are high, or they dissipate a lot of heat and need to be power resistors. you can use two 3 terminal voltage regulators, like a 7805 and 7905, which will give you an accurate voltage, but they also will dissipate a lot of heat and need heat sinks.
I'm assuming you want about 1 amp output?
You can probably use the 5 volts from your charger, although I'd use a big bypass capacitor. if the load goes above 350 mA, several things can happen, depending on the design of the supply. I can start reducing the voltage, it can blow a fuse, or it can go up in smoke.
Re ground, connect the negative lead to ground.
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One method is to drop the 7V using a 6.8V zener. be aware that zener may not exactly drop 6.800V or even 7.000V. thus you can get fairly near to the 5V required. Also this is possibe if current is say 20mA to 200mA. (At 200mA, zener will dissipate 1.4 watts.
Look for amplified zener in web , and you will find one way of getting a zener that is variable.
Best: use a three terminal regulator such as 7805.
I have erased my answer.
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I need to create a 6V DC power supply to power a pipe locater. the input voltage will be 12V DC supplied by a deep cycle battery. the power output is approx 2 Watts, but for the sake of safety the circuit should be able to provide 4 Watts or .66 Amps. I am fairly handy with electronics I'm just not familiar with voltage regulation. any tips and advice would also be greatly appreciated thanks in advance.
You need a transformer, a step-down transformer. Or a transformer, you can tap a lead out of the winding's to get 6 volts DC.
you can easily hook up the 12 volts to an LM317 regulator.
Its rated at 1.5 Amps so that plenty for your application.
This is a circuit consisting of a total of 5 components. use a potentiometer to adjust the voltage setting.
See link.
you can easily hook up the 12 volts to an LM317 regulator.
Its rated at 1.5 Amps so that plenty for your application.
This is a circuit consisting of a total of 5 components. use a potentiometer to adjust the voltage setting.
I was wondering what effect changing the resister on a buck converter has on the graphs on this website:
ipes.ethz.ch/ipes/dcdc/e_Buck_1.html
im taking electronics in college and i got confused!!
It will change the output voltage, by changing the charge time of the cap.
I would remain by having an analog regulation; analog electronics tend to be easier to setup (it’s a few resistors and opamps, maybe a handful of caps needed) instead of a proccesor + some type of PI regulator. I feel that at its price of $. in the event you include that within the feedback loop of the electrical power provide, it should regulate rather easily. I invested around 0$ US on the project (including the Giant transformer), which isn’t really bad in contrast to business supplies boasting related options.
I personally had to open it to see what wires ended up what voltage. Be aware the large red/white wires. in case you draw a, the ground potential shifts once the present drops). there are also some that output PWM which may be more accurate to utilize compared to ADC of all low cost microcontrollers. I will explain you some part of this ability supply.
They also function as aesthetic displays. It is really a LiteOn 0W PSU with +/-V, +/-V, +V, and +V standby (underside from the PSU). Here’s what it really appears like in writing: since this image is probably hard (unattainable? If you find the regulator gets warm make use of a heatsink. If you have in mind an acrylic check bench with sufficient expandability, look no further than the Dragon examination bench.
For safety, an a slow-blow fuse is within series with the key coil from the massive mother transformer (although there was that one accidental short that blackened my screwdriver which the fuse failed to catch… Warnings If you have presently developed an ATX Power Offer based bench/lab supply, you’ve already run the risks – this challenge is less dangerous. in the end, however, the regulators needed to dissipate much more heat than I thought, and so i threw out the second pcb and mounted all of the regulators on the hefty Pentium II heatsink I had scattered about.
The bases one of the TO-0 regulators used in this challenge are connected to distinctive resources, so I had to find a way to isolate them. I am not a lawyer, but I hereby release myself from just as much liability as I can, for just about any kind of injuries you sustain, or any problem you receive into. why five, and why 0′s? the voltage panel may be the prime a person. It used 5 0 pentodes in parallel because the pass aspect. also, if the ground terminal is shorted having a low-side resistor in position, the strength provide has not existing limit set.
This is how to construct an add-on variable-voltage “module” for your power supply. This venture involves the use of AC mains existing, which is more than enough to kill a person. During make use of the regulator could get scorching.
The Dragon bench supports ATX and smaller sized motherboards in addition to ATX energy supplies. It can be completed with a small ATMega withA/D input to obtained the value in the ability offer with some straightforward calculation it display individuals value. 1 delivers B+ switching (by switching the secondaries of the principal B+ and display materials), and also the other switches the .V filament power to the leading panel. These two line is then fed to regulators that are attached to the jacks about the front panel. in the end, I mounted the xx regulators straight to the heatsink with sheet metal screws and sandwiched the LM and the two xx’s having a metal bar (that we also mounted with screws) to the heatsink, isolating them with some heatsink pads I discovered within the ability offer of aIBM PS/ Model 0. the LT0 opamp is split infunction, the component a may be the voltage handle and also the aspect B may be the recent manage the two opamp output is linked together by way of diode so the one that output less voltage win about the 2nd, so if you set your voltage to 0V and your present to some and also you brief your ouput the current element will pull down his output and also the voltage will drop. I also connect with this strength provide a LCD tell you of the set stage for voltage and present-day, plus the present voltage and recent.
For a linear offer i would recommend utilizing a foldback current limiting scheme, specially on something which tends to be shorted/over driven as often like a bench supply. in the finish, however, the regulators needed to dissipate more heat than I figured, and so i threw out the second pcb and mounted all the regulators on the hefty Pentium II heatsink I’d laying around. as soon as assembled the situation is secure and usable thanks to the thickness of the acrylic and the body weight from the put in parts (Gravity at the office).
Obviously you can do that with triodes, but the optimum output voltage could be diminished. Initially you have to look for a transformer which can cope with VAC at an and one with .VAC at 00ma. after you’ve built the circuit test drive it thoroughly and measure the output voltage. the vinyl covering will safeguard the acrylic from scratches right until it reaches the end-user. after you’ve created the circuit test it cautiously and appraise the output voltage. the case design and style includesbanana/screw terminals,DPDT switches, a 0K potentiometer,LEDs,male bananna plug (for the voltmeter),LED panel displays purchased in Hong Kong, andscrew/female bannana terminals for that outputs and ground. Tips I made use of a little bit of veroboard to build this little addon. By housing the ODDs and PSU below the motherboard tray, the Dragon bench does not occupy significantly area both.
It had been based on a switching electrical power regulator. One particular issue to note, on the other hand: V down to V is an extremely large drop for the 0, and therefore even if only pulling several hundred milliamps on the +V line the heatsink gets quite toasty. It actually works, too. Use a heatsink if required. On the other hand, I must see mm fan mounts for the HDD bay area along with a mm or larger fan mount for the PCI expansion panel to further boost cooling potential. Use wise wire lengths if creating a long term connection to the ATX provide. Whilst working with the Dragon bench I noted a lot of its strengths and weaknesses in four classes. I wanted a good ability offer to test a lot of my other projects.
You simply appraise the pulse width using a timer and usually either a pin with external interrupt or a comparator input. apart from that, it truly is fantastic and that i aspire to apply it a long time. Warnings If you have currently designed an ATX Electric power Offer based bench/lab offer, you have presently run the potential risks – this venture is less hazardous. the modest sense resistor you use possibly wouldn’t make a difference a lot in a bench supply. If you need to supply filament power out the front panel as well, you need windings for those as well. the easiest way to apply this really is to use a custom made IC.
Suppose you are breadboarding a circuit that’s meant to be elope a V battery? here is the inside: I made use of my typical single-point terminals on PCB development. This generally will not make any impact on the user, as the personal computer behaves the same, but when you shutdown your pc, the motherboard can turn off the electrical power offer when it’s finished shutting down. Make sure you allow your electric power offer discharge, thoroughly unplugged from the wall plug, for a few days in advance of opening up. You can find some data onto it on my small Tek ability transformer web page. in some cases the can of the cap is sitting at elevated voltage (~0V) and so i secured them by wrapping mylar tape (the type utilized in winding transformers) all-around them.
Like an undergraduate in college I primarily based my senior task on this instance. there are also some that output PWM which may be additional exact to utilize than the ADC on most inexpensive microcontrollers. virtually. Notice the ammeter is actually exhibiting milliamps — the decimal level shouldn’t be there. This assumes you do solid-state bridge rectification when i did; should you wanna use tubes, you’ll need to account for that. MyOpenPC presents a reasonable asking price to adopt this dragon. It truly is done with a little ATMega withA/D input to received the worthiness from the ability offer with some simple calculation it exhibit those appeal. Build Quality: /0 the acrylic is clean-cut and sufficiently rounded to avoid injury.
There’s nothing sacred about the majority of the parts I used. Remove these adsRemove these ads by Registering. probably a fast-blow fuse would be much more preferable? I essentially needed to open it to see what wires had been what voltage. ) Okay! Phase History Initially, a little bit of qualifications on the average ATX energy offer: Computer system strength materials are Change Mode Electric power Supplies (SMPS) , designed to use high-frequency switching circuit components to provide a high-quality output voltage, with fantastic vitality efficiency.
Should you desire you can meet us and consult with us, our company specializes from smaller ups device to powerfulUninterruptible power supplybuilding an add-on variable voltage module for your power supply