50 Threads found on edaboard.com: Load Sensing Circuit
One of the simples methods of sensing loads is to use a low-Ω resistor (0.1Ω or less) in series with a load and connect 5/230V transformer with the 5V winding in parallel with this resistor. By doing this you have gain of ≈44, and now this signal can be used by an ordinary comparator to acitvate something (relay, LED, ..) .. (...)
Electronic Elementary Questions :: 23.09.2005 06:20 :: IanP :: Replies: 3 :: Views: 1007
I am in need of a circuit which can sense a preset load on Ac line(mains) and when the load exceeds the preset value it automatically turn on a 12v relay to shut down the ac mains circuit.and when the load falls bellow the preset value it again turn off the 12v relay to turn on the ac mains (...)
Hobby Circuits and Small Projects Problems :: 04.09.2011 12:06 :: chand00786 :: Replies: 1 :: Views: 1033
I want to make a current controller circuit for a DC Brushed Motor. Can anyone suggest circuitry?
You may start from the circuit shown in the attached figure. The load in the figure can be replaced with DC Brushed Motor. The output of the current sensing circuit is connected to an ADC (...)
Hobby Circuits and Small Projects Problems :: 29.12.2004 19:02 :: nicleo :: Replies: 3 :: Views: 797
Hi friends i am working on sine wave off line ups.I have written the code i am sine wave at no load as i am loading the inverter its shape is changing to square wave at 60 W bulb load initially its shape is changed to "D-shape" as i am loading the inverter it is complety going to square wave.I dont know what is the cause. (...)
Power Electronics :: 17.09.2009 08:12 :: praveen_palaparthi :: Replies: 3 :: Views: 896
i have searched a circuit for current sense or current monitoring and i have come across a circuit which i have attached.
i tried to figure out that how this circuit works and it goes as follows.
1st consider that load is not present. then Va = Vb and and transistor is in cutt off state where Vc (collector voltage) = (...)
Analog Circuit Design :: 01.06.2010 19:58 :: engr-sajjad :: Replies: 7 :: Views: 2217
you can connect the load like you say and in parallel you can connect two resistors in serie, 10K and 1 K and then monitor the voltage measuring the 1K resistor. Or you can change the values of the resistors for another level of voltage in one of them and after that you can apply a bridge of diodes for generating DC.
I hope it helps.
Analog Circuit Design :: 20.02.2013 16:55 :: alberto1683 :: Replies: 6 :: Views: 1822
In SMPS design of attachment file,
I found that Overvoltage and Overcurrent are sensed from secondary of Flyback trasformer.Overload current sensing is from primary.I would like to know some questions about the circuit like this above.
1.Can current and voltage sensing circuit be connected to either side (...)
Analog Circuit Design :: 05.06.2005 01:04 :: aunglay :: Replies: 5 :: Views: 898
CT need a resistor load (fixed value resistor specified by CT manufacturer), look at application circuit suggection or electrical specifications of your CT. Do you have that resitor load? Vithout proper termination your reading could be in error also with current passing if load side is open circuit by (...)
Analog Circuit Design :: 06.04.2007 23:08 :: tekno1 :: Replies: 4 :: Views: 770
I m currently working on project named, Butt Welding controller.... In this pro TRIAC (BTA41) is used to control the load voltage(AC)....
89c52 microcntroller is used to provid Variable voltage To fire the TRIAC.... Via DAC0808....
Now finally i want to disply the ACTUAL load vltage on my display.
Here i m using ADC0804 to rread t
Microcontrollers :: 13.06.2007 03:47 :: eamol :: Replies: 1 :: Views: 1166
I am doing a project for a module that controls the switching of a few different loads. A microcontroller will be controlling most likely a MOSFET to switch the current to the load. The module must be able to "sense" the load, in that the microcontroller must know if a a load open-circuits - such as a bulb (...)
Analog Circuit Design :: 15.03.2008 13:53 :: Rando86 :: Replies: 6 :: Views: 770
if you don't need to be accurate with the current, you can make your own.
Best is a toroid, wind maybe 2 turns of line voltage on it, take the active wire complete with its insulation.
then get some Cu winding wire, and wind on 50T at least. Now you will get a voltage on this secondary winding when current flows through the active wire.
Electronic Elementary Questions :: 23.11.2008 19:39 :: xaccto :: Replies: 3 :: Views: 1083
I need some help here.. I have a voltage sensing circuit that is supposed to operate an AC contactor (solenoid type) when the voltage reaches a certain threshold. This portion works fine but the AC waveform to the coil looks terrible. Very distorted at the zero crossing and top looks chopped. The contactor is also chattering.
I selected a zero
Analog Circuit Design :: 20.04.2010 15:12 :: Freddybaby :: Replies: 0 :: Views: 522
A very cheap method to make a CT is to use a small transformer and remove its secondary low voltage winding. Then use a single turn of think wire to serve as high current primary. The high voltage winding can now be used as current secondary with a suitable resistance as its burden (load, shunt).
Microcontrollers :: 15.09.2010 14:22 :: techie :: Replies: 17 :: Views: 1243
but i need zero cross detection for load current.. if i use CT then it have two terminals, but this circuit have three terminals.. how i can use it.I didn't get what you are trying to achieve.
Microcontrollers :: 24.06.2011 00:21 :: Tahmid :: Replies: 5 :: Views: 3627
Help! Can someone clarify to me how sense current with EI current transformer ? it o\p we for over load sensing .....
pl help me
Power Electronics :: 29.03.2011 12:54 :: sahu :: Replies: 6 :: Views: 463
are there differences with the supercapacitor position among the setup:
*full bridge rectifier (4 1N60 germanium diodes)
*dc/dc converter (TPS61200)
*supercapacitor (Cellergy 20mF 4.2V Ultracap with ESR = 0.36milliohms)
**full bridge rectifier AND dc/dc converter using LTC3588
a.) piezo/other transducer -> full bridge rectifier -> supercap
Power Electronics :: 08.06.2011 05:50 :: jeromekang :: Replies: 6 :: Views: 975
It maybe an SMPS based UPS. Switching power supplies do not function properly without a minimum load, eg, problems in feedback loop, inductor, etc without minimum load. So, the UPS may turn itself off to protect itself.
Some photos would help. Then, it can be better understood.
Service Manuals, Requests, Repair Tips :: 23.07.2011 05:30 :: Tahmid :: Replies: 13 :: Views: 4956
Do you manage delay time for initial current(surge load) in your overload protection circuit.
Electronic Elementary Questions :: 10.09.2011 11:02 :: pnjbtr :: Replies: 6 :: Views: 686
So you want to measure alternating current, right? There are two ways. One is to use a shunt resistor, and the other is to use a transformer.
First approach has advantage of being simple and cheap, but also contributes power loss in circuit. Resistor can be really small (like 0.2R or something). Then you amplify and measure the voltage drop acr
Microcontrollers :: 14.11.2011 03:07 :: poorchava :: Replies: 2 :: Views: 881
it will just be a digital output where the load(realy most probably) will be driven using a fet for transistor.
the input supply will be from 24 to 60v but we have to implement a limit of .5A at 60V. at other voltages also shortcircuit protection must be there
Analog Circuit Design :: 15.12.2011 04:36 :: vishnupg :: Replies: 8 :: Views: 1968
Since it's half-bridge, for short-circuit protection, you should use a current transformer in the path of the power transformer.
For overvoltage protection, step down the DC bus using a voltage divider, eg, by a factor of 100. So, 300VDC gives 3V at the output of the voltage divider. Say, you realize that overvoltage is defined for voltages greater
Power Electronics :: 03.01.2012 12:02 :: Tahmid :: Replies: 7 :: Views: 2046
I am driving motor with IR2130(3phase) and controlling the IR2130 with PIC. I am using 5 12v/7a batteries.
The system is working like this:
First I am starting the motor to run to one direction for 2 seconds. I am measuring the current. Then I am
making the motor to run in reverse direction for two seconds. And I am measuring the current
Power Electronics :: 17.04.2012 12:32 :: losturcos :: Replies: 16 :: Views: 841
But I know that Current Transformers with op-amp circuits can be used to interface microcontrollers. What I need is a current sensing circuit interfaced to ADC pin of PIC16F877A.
I fund a schematic of "Ideal rectifier with an Operatioanl Amplifier" and tested it with circuit Maker Student CMS60.
If you use a (...)
Microcontrollers :: 23.04.2012 08:51 :: paulfjujo :: Replies: 6 :: Views: 1084
pls can any one help me with an inverter overload circuit diagrams, pls if there is any. mail to
Hobby Circuits and Small Projects Problems :: 15.09.2012 15:19 :: fmtech :: Replies: 2 :: Views: 1545
You would need a means of measuring the current and determining if it is within the overload limit.
Shunt may be used. But with increasing power, required resistance will be VERY low to keep losses low. Keep the losses in mind when designing the circuitry.
You may look at other current sensing methods, such as hall-effect sensor.
Hobby Circuits and Small Projects Problems :: 17.09.2012 08:58 :: Tahmid :: Replies: 2 :: Views: 1302
One circuit you could use is:
Sense the current flowing through (a shunt may be used, or you can use any other type of current measurement device). Compare the value against a preset value. If the measured current < reference current, switch on a MOSFET that permits current flow through the load. Keep on sensing the current. If the current (...)
Electronic Elementary Questions :: 25.09.2012 14:13 :: Tahmid :: Replies: 8 :: Views: 519
load cell will give analog output. For processing the information, you have to connect ADC between load cell and microcontroller.
Microcontrollers :: 04.03.2013 00:37 :: learner71 :: Replies: 10 :: Views: 772
It seems your regulator TL2575 is maybe not configured properly. Have you checked the output of the regulator with a multimeter, when it is connected with load??? Try using LM7805. It requires no voltage configurations...
Analog Circuit Design :: 13.04.2013 07:45 :: Genovator :: Replies: 9 :: Views: 417
i need to develop constant current circuit (4A +-10%) in temperature range (-45 to 85 C). i mean constant current in temperature range, circuit will work 1 sec. supply voltage 28 V. main problem that my load can be from 1 to 7 ohm (random). i don't know if anybody here had experience this problem and should please guide me (...)
Analog Circuit Design :: 13.04.2013 16:06 :: z_mx :: Replies: 20 :: Views: 736
Guys .. i need to write a C code for sensing the voltage and current using the microcontroller P89V51RD2.. in LCD i want to display the exact voltage value i.e. like 8.2V and also the current..and i also want give an reference voltage and current and when the V,I is less than the ref value i have to cut the supply to the load else give supply.. for
Microcontrollers :: 14.06.2013 04:03 :: Santhoshksk :: Replies: 6 :: Views: 317
Being the flyback circuit the one that draws most of the current, cut the connection ( or thrace ) between the capacitor after the rectifier and the HV generator circuit and replace the load wit a bulb lamp 230 V 40 or 60 W ( 40 w for 14 or 16 ", 60 W if higher ).
Turn On the TV and verify the voltage across the lamp.
Service Manuals, Requests, Repair Tips :: 28.12.2003 12:54 :: FANT :: Replies: 7 :: Views: 1819
the schtematic given is only a block digram
for this purpose u can use feed back amplifier for given the constant input.
at load should have to connect the volt meter and make your desire output as a 0 volt so the variations occurs u should read directly, as same for the ampere meter.
Analog Circuit Design :: 02.02.2006 07:45 :: vicky :: Replies: 14 :: Views: 1327
Hi, you can use simple comparator, like a LM393, all is depending from this do you have some available part in your circuit that can be used. The diagrams from IanP is good, but have one big disadvantage, the LED is on when the voltage is in nominal range. There are two problems:
1- Via the led you will have a current that will be extra load, and
Microcontrollers :: 06.05.2006 08:59 :: Tohu :: Replies: 6 :: Views: 1208
load is pure incductuve and this is exact application circuit.
Drawing from scop screen.
I didn't show the Mos driver.
Professional Hardware and Electronics Design :: 15.10.2006 20:07 :: bunalmis :: Replies: 13 :: Views: 1753
Cars have a voltage regulator systems which fixes the output voltage of their generator to the desired value. It basically consist in a transformer where the regulator monitors the secundary volage and according to the load in the secundary circuit increases or decreases the voltage in the primary circuit of the transformer. You can (...)
Electronic Elementary Questions :: 26.10.2006 05:25 :: Sal :: Replies: 3 :: Views: 643
Ok, I am a little confused. What does item #1 mean? Are you saying that the phone line is captured immediately at the first ring without the relay being energized? If this is the case, then I think you need to either reduce the value of the series capacitor on the ring detection leg or add additional resistance to only that portion of the circui
Hobby Circuits and Small Projects Problems :: 07.03.2007 08:22 :: banjo :: Replies: 5 :: Views: 2893
I am building a CV-CC supply which would output a 50ms pulse of the set output current to a load which would be up to 5 ohms.
I will set a current of 1Amp (using fixed resistor prior to the load) by replacing the load by a short circuit,vary the voltage and then connect the load for actual experiment. (...)
Analog Circuit Design :: 05.11.2008 06:48 :: abicash :: Replies: 0 :: Views: 377
I want to generate 4 pulses at different load of a diesel generator say 1st at 60A second at 70 and third ad 80 and then at 90A.
Please explian the circuit/hardware for this. Will CT with shunt will be correct method or is there any other easy solution to this.
Microcontrollers :: 13.05.2009 07:23 :: dani :: Replies: 3 :: Views: 726
I'm driving a load with a pnp transistor. The current is 1A max, the voltage is 24V. I want to turn off the output above this current but i don't want to use a power resistor and do not want to use a complex circuit. Can you suggest me simple yet effective current limiting scheme for this task without using a power resistor? Thanks.
Hobby Circuits and Small Projects Problems :: 28.05.2009 03:31 :: seyyah :: Replies: 1 :: Views: 5356
Whether to connect the sensing load to ground or not depends on where the supply source comes from. Many sistems use an external Vcc to power the load. Voltages up to 24V may be required if using many loads in series. Nothing wrong if you intend to use only one sensing load. Please also take (...)
Electronic Elementary Questions :: 07.05.2010 17:12 :: pauloynski :: Replies: 5 :: Views: 2574
I am a newbie and am trying to design an Amp-Hour meter using ATMega16. My main constraint is that I need to measure on the High side. The second constraint is that the high side current measurement ICs are not available locally in Karachi, Pakistan.
The current measurement is for a UPS battery (12VDC car battery). Current sensing is to b
Analog Circuit Design :: 03.08.2010 01:23 :: aurangzebhaque :: Replies: 0 :: Views: 1116
I do not understand your diagram but assume that you want to measure the terminal output voltage of some solar panels in series (40 V) as well as the load current out of these panels.
To measure the voltage you must divide the 40 VDC down to 5 V. I assume that your A2D can handle a 0 - 5 V inputs The divide circuit is simply two resistors in serie
Hobby Circuits and Small Projects Problems :: 18.03.2011 14:33 :: klystron :: Replies: 2 :: Views: 1532
this means differential amplifier with ratio between driver to load transconductance (Gm/Gload) <10. In principle from your spec follow that even simple complementary (i.e. P-type + N-type sensitive input) regenerative amplifier (without analog preamplifier stage) can be enough.
Analog Circuit Design :: 15.06.2011 06:57 :: mikersia :: Replies: 7 :: Views: 602
Remote sense isn't remote control, it's just a means to compensate voltage drops at the cable by sensing the voltage at the load. A remote controllable power supply should have at least terminal pairs for voltage and current setpoint. If your instrument doesn't have it, then it's probably not designed for remote control.
Microcontrollers :: 21.09.2011 15:43 :: FvM :: Replies: 11 :: Views: 460
A buck regulator can easily be made to control the output from 0.0V to max, in a smooth fashion, this is never done however for two reasons; 1, if the buck switch fails short full volts will be applied to the output (lots of smoke in the load) & 2, a straight buck converter provides no isolation - so if you touch the o/p you will get a mains shock
Power Electronics :: 04.12.2011 02:41 :: Orson Cart :: Replies: 2 :: Views: 519
At first I would think it is logical to charge at 14.5 V. It automatically cuts off charge when Spec #1 is reached.
However you will find that charging current is greater when you apply a higher volt level, say 24 V. My solar panels had enough cells to output that amount, with no load attached. I think the manufacturer experimented until they
Analog Circuit Design :: 22.01.2012 23:34 :: BradtheRad :: Replies: 3 :: Views: 879
What I dont understand is why your water heater would trigger this resonance, as it should have fairly linear sinusoidal current from a linear resistance and stead AC voltage.
I still say it's due to the voltage drop from the extra load on the mains wiring.
Electronic Elementary Questions :: 29.04.2012 05:25 :: FoxyRick :: Replies: 34 :: Views: 613
Here is a good example of how to do it using a series shunt current sensing for OK. but how can sense AC current ?
Microcontrollers :: 13.10.2012 13:03 :: sahu :: Replies: 8 :: Views: 1511
energy monitoring using pic16f877a_which sensors to use?
I m trying to build an energy monitoring application. I have to measure power consumed in a domestic environment, and power generated in a solar panel. I am emulating the domestic environment with a load built with two 40W lamps.
I have some doubts regarding the sensors that i
Microcontrollers :: 03.12.2012 06:26 :: pcsandhya82 :: Replies: 3 :: Views: 402
I have seen this foldback circuit and would like to use it however I am struggling to understand how it works?
The rather brief writeup with it says:
In normal operation, Q1 is saturated. When load attempts to draw more than this saturation value, base current of Q1 cannot maintain saturation so vol
Electronic Elementary Questions :: 10.05.2013 17:10 :: otacustes :: Replies: 4 :: Views: 262