# What is Regulator: Definition and 149 Discussions

A voltage regulator is a system designed to automatically maintain a constant voltage. A voltage regulator may use a simple feed-forward design or may include negative feedback. It may use an electromechanical mechanism, or electronic components. Depending on the design, it may be used to regulate one or more AC or DC voltages.
Electronic voltage regulators are found in devices such as computer power supplies where they stabilize the DC voltages used by the processor and other elements. In automobile alternators and central power station generator plants, voltage regulators control the output of the plant. In an electric power distribution system, voltage regulators may be installed at a substation or along distribution lines so that all customers receive steady voltage independent of how much power is drawn from the line.

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1. ### Predicting Remaining Pressure in Compressed Gas Cylinder

Well, it's been nearly 10 years since my last post, and it's been about that long since I've thought about ideal gases, so here we go :smile:. Description of Setup I have a system that uses compressed gas cylinders as a source to slowly purge an optical payload. The source is 12x compressed...
2. ### Volumetric flow rate of nitrogen through relieving pressure regulator

Hello all, I'm having trouble figuring out the volumetric flow rate upstream of a relieving pressure regulator used on a 1/4" OD nitrogen line. Upstream of the regulator P=100 PSIG and T=70F, while downstream P=80 PSIG and T=70F with downstream consumption at q=4 L/min or 0.91 SCFM (at std...
3. ### Manual vs. Auto Drain Air Sets: Which is Best for Filter Regulators?

Difference between manual drain air sets (filter regulators) and auto drain air sets?
4. ### How to start LM317 regulator from 0 Volts

I want to make power supply from LM317 which starts from 0 volts instead of 1.25 volts. I have seen method of using diodes and zeners but I think there maybe a better way. We know Voltage across R1 (see image 1) is 1.25V. So if I take the output across R2 rather than at OUT of IC, won't I get...
5. ### Electrical Automotive Alternator with External Regulator Light stays on all the time

My problem started when I took my alternator apart to grease bearings when I put it back to together dash light came on so took it apart seen wire to one of the brushes was broken soldier back together it work for a short while the light was back on seen soldier had broke again so I changed...
6. ### Automatic Voltage regulator rating

Hello Everyone, I'm here in a country which has a 220v single phase. My wife's \$700 Microwave/Convection oven just arrived from the US. The rating of this appliance is: 110v, 1750 watts, 15 amperes. I've talked to suppliers here and was told to buy an AVR with a rating(wattage) 5 times more of...
7. ### Load resistance in voltage regulator

Homework Statement [/B] I want to find the minimum resistance ##R_L## so as to maintain ##V_z##(voltage of the zener corresponding to the minimum current ##I_{z_0}##) across the same resistor ##R_L##. Homework Equations ##V_z##(voltage of the zener corresponding to the minimum current...
8. ### Is this a good GM tube voltage regulator and rectifier?

https://www.circuit-diagram.org/editor/ Hi, I was wondering if this is a good voltage rectifier and regulator for a GM tube power supply? The AC supply is approximately 500V, and the strange component at the bottom is a voltage regulator tube. Seems to work OK but I don't have any test equipment...
9. ### Casimir effect with Gaussian regulator

Homework Statement Calculate the Casimir force in 1D using a Gaussian regulator. Homework EquationsThe Attempt at a Solution I reached a point where I need to evaluate a sum of the form $$\sum_n n e^{-\epsilon^2n^2}$$ Can someone help me? I didn't really find anything useful online. I thought...
10. ### Ground current for a voltage regulator

Homework Statement Homework Equations 3. The Attempt at a Solution [/B] Currently working on the question relating to the ground current on the voltage regulator, 7805 (data sheet included below) I am very much unsure what to calculate here I'm assuming the current to ground is the input...
11. ### Gas pressure regulator model in Simscape

Hello, I want to develop a pressure regulator model in simscape. The model will be the springloaded direct acting system and the aim is to target outlet pressure, temperature and flow rate by giving input parameters as pressure, temperature, spring stiffness, length and preload, lever(it is...
12. ### How does a voltage regulator differ from a zener diode?

I am making a circuit with Arduino. It is known that the recommended power supply of an Arduino is 7V - 12V. I am going to use a 9-0-9 (230V to 9V) transformer, convert the stepped down voltage to DC, and feed it into the Arduino through the Vin pin. Now, there are chances that the input AC may...
13. ### LM317 (not Buck) Linear Adjustable Regulator problems

I purchased a buck regulator I apply 12 volts dc to in and get 11.5 volts out turn screw on pot makes no changes measured pot goes from 4k to zero ohms if one unhooks connection to terminal 1 adjustment to LM317 will this give you the minimum voltage of about 1.5-1.6 volts? I want 12 volts in...
14. ### Automotive How to model a CNG pressure regulator?

I need a help with 1D simulation of a CNG pressure regulator. I have to model this valve in a software called GT power/GT suite. The model has a inlet, ball poppet, piston with spring, outlet and a pipe for balancing the valve. Maybe someone who has experience about modeling this kind of...
15. ### Is the STMicroelectronics L7912CV Voltage Regulator Suitable for a +12V Output?

[mod note: thread moved from homework forum] I have this Mouser voltage regulator https://www.mouser.com/ProductDetail/STMicroelectronics/L7912CV/?qs=sGAEpiMZZMug9GoBKXZ75xbXFDWiKqpmvrbz5I0HaKg%3D Wired according to datasheet https://www.mouser.com/ds/2/389/l79-974159.pdf see insert photo...
16. ### Power dissipated across a transistor regulator

Homework Statement [/B]Homework Equations For the 1st part Ohms law and resistance across zener is 10V[/B] I can't get 2nd The Attempt at a Solution For 1st part I took Vi/p = 18V[/B] Putting KVL for left loop of source-->collector-->base-->zener-->ground 18 = Vcb + 10 So Vcb = 8V And Vbe =...
17. ### Need help with voltage regulator circuit that uses 7805

Well let me explain. I've finished a circuit that consists in a microcontroller unit (in this case a PIC16F877A) that is connected to a LCD module, a keyboard and a RTC module (via I2C protocol). As far as I know all of them require VCC (=+5V) for operating so I needed to create a +5V regulated...
18. ### Understanding 'C Code' & 'No.' in Buck Converter Regulator Datasheet

I have recently come across a datasheet for a buck converter regulator that uses the terms "c code" and "No." for certain capacitors but when going to the manufacturer datasheets for these capacitors they make no reference to any "c code" or one single number for a capacitor. If anyone could...
19. ### Discrete LQR regulator and Bellman's principle

Hello everyone. Iam studying the LQR regulator in optimal control theory right now but Iam having some issues in understanding the approach of Bellmans principle. As far as I have understood, in Bellmans dynamical programming approach, one goes backward in time to find the optimal Gains K...
20. ### Series Pass Regulator Design Guide: Transfer Function & Compensation

Does anyone know of any good references for a detailed guide designing a series pass regulator along with compensation? I'm having some trouble getting the plant transfer function and would really benefit from some book or video or application note on this topic. Even an older thread on...
21. ### Voltage Regulator Circuit Calculations

Hey Guys, so I'm just in need of some help in relation to finding the output current after the voltage has been dropped to 6V. The circuit has an input voltage of 24V and I've attached a photo of my circuit diagram. Hopefully I haven't made any errors in that, but I've tested the circuit and it...
22. ### Increasing voltage regulator current

I'm looking to draw about 6A. I have an LM338 regulator that can supply up to 5A. Searching the internet I came across this schematic, So basically when the 1R resistor drops 0.6V then the transistor conducts the remainder of the current. I calculated my own values for those two resistors. Was...
23. ### LDO voltage regulator stability

I haven't done any Bode plots before, and so I'm reading about LDO stability and I came across this file, which I am trying to understand: http://www.ti.com/lit/an/slyt194/slyt194.pdf Under the stability analysis, it names the poles and zeroes. How are these calculated? I assume that the...
24. ### Mass Flow Rate of Pressure Regulator

Hey, I have an air tank that is at a set pressure, say 3000psi, and I have attached a regulator to the end that regulates the pressure down to 800psi. As the valve on the tank is opened the pressure and the mass in the container will decrease. If there was no regulator the mass flow rate would...
25. ### Mass flow rate through a regulator

Hi, We have a canister at a set pressure (4500psi) full of compressed air. A single stage pressure regulator is fitted to the canister that reduces the outlet pressure to 850psi. The flow from the regulator is then used in a divergent nozzle to create a thrust force capable of lifting a small...
26. ### Compressible air flow from a tank through a regulator

This is probably a simple question but I am really struggling as to where to start. We have a tank of compressed air, Volume of tank (V1) = 0.2litres Pressure of tank (P1) = 206.8 bar Regulator Pressure (P2) = 58.6 bar I would like to find the volume of air that can pass through the regulator...
27. ### Temperature in the regulator valve of a cylinder

Homework Statement There is a cylinder of oxygen connected to a valve (A) and then to connected to a regulatory valve. The volume of both valves and the pipes between them is Vr and can be disconsidered in regard to the cylinder's volume. The oxygen can be considered a perfect gas with...

I'm looking for an example of CFD analysis on a pressure reducing regulator. I think may be fairly complicated because the main valve position is not fixed but rather controlled by the pressure differential acting across the valve, the main valve spring, and the load spring minus the pressure...
29. ### Pneumatic regulator idea/question

Hi guys, I have a quick question that someone might be able to assist me with. As a job i build waste water treatment plants and lately we have moved from using an electric butterfly valve to a pneumatic pinch valve. We have a common air supply of 6 bar and we now regulate to 3 different...

Homework Statement [/B] Calculate the output voltage range for the adjustable voltage regulator circuit shown in FIGURE 1. I have read an older post and have understood how the formula works but I am thrown off by the inclusion of the 50uA current coming from the Adjust Pin. How would I...
31. ### Understanding the LM2576 Step-Down Regulator

Hi, I am working on a little electronics project where I need to convert 15V DC to 5V DC. I was hinted at the LM2576 (datasheet) because it is easy to use and has a built in current limit which is just what I need. The functional block diagram (p12) has a nice display of the internals of the...
32. ### Linear quadratic state regulator

Dx (t)=(B u (t) - v (t))dt B is 7x3 which is known U is 3x1 unknown V is 7x1 which is known dt is step size 0.1 A matrix is equal zero How to design a controller that will drive state to zero
33. ### How Can an Op-Amp and Diode be Used to Convert 12V to 5V for a PIR Detector?

Homework Statement FIGURE 3 (on page 7) shows a PIR (passive infra-red) detector and its associated amplifier, as used in burglar alarm systems1. (a) The detector is powered from a 12 V unregulated supply that needs to be stepped down to 5 V. Design a suitable 12-to-5 V voltage converter using...
34. ### Getting rid of speed regulator

I just installed this bike kit http://www.ebay.com/itm/36V-500W-Geared-26-Front-Rear-Ebikeling-Electric-Bicycle-Conversion-Kit-ebike-/271923152076?var=&hash=item3f4fe204cc:m:mDQBWD22DB6VOvwhv_g145g It is a LED Display with a front wheel hub How do i get rid of the speed regulator. The ebike can...
35. ### Lagrangian of a centrifugal regulator

Homework Statement Homework Equations L = T-V The Attempt at a Solution I got a forumla for the lagrangian as
36. ### Buck regulator design, which parts can be slightly different?

I want to build http://www.hobby-hour.com/electronics/lm2576hv-adj-buck-regulator-schematic.png From http://www.hobby-hour.com/electronics/lm2576-step-down-switching-regulator.php I might not be able to source exactly the same parts. I assume I have to use the same IC, but could I use a, say...
37. ### Fix a Regulator in Circuit: Step-by-Step Guide

Hello guys, I have a question and I would really appreciate your help. In a circuit, how do we fix a regulator, if air goes through? What do we have to adjust, or remove from the circuit? Best regards
38. ### Adjustable Voltage Regulator Output Voltage Range

Homework Statement FIGURE 2 shows an adjustable voltage regulator using the LT1083 .The LT1083 develops a 1.25V reference voltage between the output and the adjust terminal. By placing a resistor R1 between these two terminals, a constant current is caused to flow through R1 and down through...
39. ### Engineering Basic circuit operation of voltage regulator

Homework Statement Homework EquationsThe Attempt at a Solution I need to know if my understanding of this circuit is correct in terms of R1, R2, Q1, Q2. R1 is a sensing resistor and when Q1 senses a voltage drop at its base, it switches on and passes current around the regulator. I think...
40. ### Determine supersonic flow velocity, tank to regulator topipe

Hello All, I am trying to figure out the solution to a problem I am trying to do for fun. I've been trying this for a while and has annoyed me so any help is greatly appreciated! I attached a picture of the problem/ control area to help...
41. ### How can I analyze the effects of this orifice in a pressure regulator?

Hi folks, Firstly a little background, I work for a company that manufactures gas pressure regulators. Last year I was a machinist studying for my HNC in manufacturing engineering. Since passing work has given me the opportunity to work in the product engineering office as a product tester and...
42. ### Voltage division of a 5v regulator output?

So here's my problem. I have a pair of noise-cancelling in-ear headphones, and they require a AAA battery. Batteries are expensive so I only use rechargeable ones, but those have a lower capacity (700 maH) and don't last long. I want to make it last longer by putting several of them together...
43. ### Compressor Water Cooled Chiller Thermal Calculations

Hi All, Is there a list of thermodynamics equations regarding the chiller process from condenser, evaporator, compressor to the regulator. Say I have chiller load at 90%, what set of equations could I use to determine the supply temperature of chill water and condenser supply temperature to...
44. ### Positive and Negative Adjustable Current Supply (3.3mA)

Hello, I was looking for some sort of chip/IC that would accept a digital input of say 4-5 bits and that would adjust an output current. I am looking to have a +/-3.3mA current applied to a resistive load. It would also be helpfull (for testing purposes) if I could adjust the inputs so that I...
45. ### 28->24 volt regulator keeps blowing my 24->10 regulator

Hey guys! I have been having a lot of problems with a board I am working on. The board was originally designed for 24 volts, but my input is 28 (non negotiable), so to make things easier than redesigning the whole power circuit, I am just doing a step down to 24 right when it goes into my box...
46. ### Voltage Regulator: TR1 & TR2 Current Regulation

Homework Statement https://physicsforums-bernhardtmediall.netdna-ssl.com/data/attachments/66/66455-bb02bb0d3c839e914352eb0379b453f2.jpg Homework EquationsThe Attempt at a Solution Transistors TR2 and TR1 amplify the current being regulated through the regulator. The current gain of...
47. ### Calculating Maximum Load Resistance for MC7805 Integral Regulator

Homework Statement My question concerns MC7805, integral regulator, used as a high current voltage regulator. See figure attached. Now, I am told that Ry=7.5Ω and that Q2 is on the verge of conductance with VBE,on=0.5V. Using the Max. Quiescent Current from the manufacturer's data sheet (see...
48. ### Choked Flow in 1/4" Pressure Regulator at 3.5bar

Is it possible to have choked flow in a 1/4" diameter pressure regulator with pressure difference of 3.5bar?
49. ### Air Pressure Regulator velocity

I have a pressure regulator that has working the range of outlet pressure 0 to 2 bar, inlet pressure 5 bar, flow rate of 600lit/min and the regulator has 1/4" outlet port (6.35mm). whole data is according to manual I have not tested the regulator. But for flow rate of 600lit/min the velocity...
50. ### Pressure regulator flow rate

Is flow rate at inlet of pressure regulator ( not relief valve) equal to flow rate at outlet ?