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Swagatam.
Hi. I am a Senior High School student . Our research is the same as you, but we are using photoresistor and LED bulbs. our goal is to decrease or increase the light in LED Bulbs depending on what the sensor(photoresistor) can detect in an environment(Ex. If your LED bulbs is bright and the environment is slightly dark ,the Led bulbs will decrease its light because of the photoresistor and it will balance into the environment) and it can also save more energy because we are using LED Bulbs. Our problem is that we do not know how to write a procedure in making our research and we do not know how to program a code in our research. If you have time will you please help us in making a procedure and a program code of our research.Please reply soon. Thank You
..
Hi, sorry my coding skill is not good, so can’t help you with this project. I wish I could do it!!
Hi sir thanks for fast reply. How about the procedure of making our research? If you have time please help us. We really need your help. Thank You..
Hi Tristan, if it’s without Arduino then I can help. For further discussion please post your comment in some other related post.
hi sir.
as you know pir sensor are expensive even the pet frendly tipe. i bought by an electronic shop the one’s without casing HC-SR501 i think but looks exatly like the ones that are on your explaining of pir how it works
im new to to electronics but know an very little bit. i saw your explaining on how an pir sensor work. but im trying to make it pet frendly. the sensitivity adjustmen is not low enough and even pic up an small leaf, bird at day and bat at knight. can u help me what to do or must i change the pir sensor thats in the middle of the module and if that’s the case. i cant find an part no so i can order it. i think its the HC-SR501
thanks alot and I’ll appreciate you help.
Hi johan,
you will need a filter attached to the PIR otherwise it will be extremely sensitive to all IR sources. The HC-SR501 is the recommended one which you will actually need to purchase. You may find other alternatives too, but the front lens is crucial for stability and a controlled sensitivity.
hi sir. thanx for the fast reply.
i am not sure what tipe of filter if its electrically and what or where and how to connect it or shielding in front of the ir or infront of the small white lens and what tipe of meterial to use.
sorry for asking details but dont know much ????
Hi Johan, the filter is in the form white dome shaped plastic, it can be fitted in front of the lens.
Hello Mr. Swagatam, thank you for the quick response. I have some ferrite transformers from PC sources .. My question is …. How can I use them for investors? From already thank you very much.
ATTE: Carlos from Argentina.
Hello Carlos, ferrite transformers require strict calculations, so I don’t think they can be used randomly without knowing the winding details accurately.
Hello, good afternoon, I am a faithful follower of the website. I have a question, I have an inverter with lm555 and modified wave cd4017 .. the problem with the transformer inverters is that iron without load also consume .. How can you make it more efficient? From already thank you very much.
Atte: Carlos from Argentina.
Thank you Carlos, Iron core transformer will consume some power, that’s the reason these type of inverters are less efficient. There’s no way to improve this except using a ferrite transformer…or may be you can try using a torroidal iron core transformer which will help to improve the efficiency quite drastically compared to normal E/I core iron transformers.
Thank you Mr Swagat for you time and energy helping people who want to know about electronics. I’m new here but I know you be of good help thank you sir
Sure! You are most welcome Osei!
Dear Sir
I have a small meat grinder that stopped working, I took it apart and checked the motor, it’s a 220-volt dc motor, I found an old rectifier and connected to the mains and the motor works but the motor has a lot of starting torque and I’m afraid it might strip the plastic gears, I was thinking about a soft starting circuit but I have no idea how to do it, also I live in the Philippines so electronic components are hard to come by, we only have Lazarda and a few other online stores but I haven’t found anything that would solve my problem, also I’m quite poor so it would have to be something at a reasonable price, please help
Dear Alan,
You can do one thing. Buy a light dimmer circuit, and connect your motor in series with it. You can manually keep the dimmer a lower control when you want to switch ON power. Then once the motor is ON with a slower speed, you can increase it to full speed manually. make sure to attach a large heatsink with the triac of the dimmer circuit
Sir;
We are currently final year B.Tech students at Govt, Model Engineering College and doing the final year project on this topic.
We had first modulated 1 kHz sine wave using a PWM modulation at 40kHz by SG3524 IC.
Then we used an L293D IC to drive an parametric array of ultrasonic speakers.
Our parametric array includes of 14 ultrasonic speakers arranged in 7 rows.
A modulated signal and an unmodulated carrier of 40 kHz is fed to each alternate rows.
Then we had successfully heard the tone of 1 kHz.
After that we introduced an music signal from mobile phone via audio jack and we were only able to heard a feeble sound at the output and which is also above a particular frequency.
If we input an audio signal of a speech, its absolutely nothing we heard.
Can you suggest a solution to this situation..
Hi Athul,
Your approach is perfectly correct, however the input has to be from an amplifier with a relatively high amplitude. Because we are using digital ICs here, which will be able to detect the input signals only if its around 5V minimum. A signal from a phone or any headphone jack will be in millivolts which the digital ICs cannot detect.
So make sure the input music amplitude is at least over 3V for effective detection.
Thanks sir..
One more thing, is a pre amplifier using LM386 enough or do we need any other audio power amplifier to serve our purpose.
Hi Athul,
Yes LM386 amplifier should work since its peak output will be equal to its supply voltage.
Thank you, Sir.
Let me check it and inform you later.
Dear Sir,
Very nice work by you.
Pls. advice me how to generate 1000VDC ( Max 1 A)from mains 230Vac, need simple Circuit. I tried with Voltage multiplier. I got >1000VDC with ‘C’ and Diode.
But it is not capable of handeling load even 10mA. Pls. suggest.
Thank you Uday,
for getting 1A you will require a transformer, because capacitors won’t give you 1A unless they are substantially big.
You can try the second design from this article, this s two stage multiplier and will give you only 500V RMS, you can add another series stage to get 1000V
https://www.homemade-circuits.com/generatoralternator-ac-voltage-booster/
use 5uF/400V PPV by adding 5nos 105/400V caps in parallel on each. This should be able to give you around 100mA. Increasing the cap value will proportionately produce more current
Thank you very much Sir.
For 1000V, should i have to increase Voltage ratting of capacitor also.
It is not required, 400V is enough. These will come in series therefore will be ultimately higher than 1000V
Thank a lot.
you are welcome!
Dear Sir,
One more suggestion required.
I have Diode bank of 100no, connected in series.(SF4007, Max Rev=1000V, iF=1A). I wnt to test this bank on full load.
Considering 0.7 drop of each diode x 100 nos=70 Volt. How much Max DC Voltage and current i can give to test this bank.
Hi Uday,
If the input is 220V AC, then the average output will be 110V – 70 = 40V DC but the peak will be 220V – 70 = 150V DC.
Current will be 1 amp if the diodes are mounted on heatsink, otherwise only 100mA to 300mA can be extracted without flaws.
please in need automatic phase selector from any available phases with circuit diagram.. 3phase circuit is no longer in your box again please add it for us sir. thanks in advance
Hi Tobi, you can take the help of the following circuit:
https://www.homemade-circuits.com/extracting-single-phase-voltage-from/
But am making a transistor amplifier, can it be replaced with transistos instead of MOSFETS & give good results?
I think BJTs will also work in the referred diagram, you can try it out. But a PCB is a must in any case to avoid connection faults
Hello Sir, well done in all?
Am so great full for the above formula U gave me but I have two challenges in the above circuit I gave U where transistor TR3 heats up but its temperature starts slowly and increases with time and also resistor R4 heats up but its temperature tends to be constant.
But when I disconnect off the BASE of transistor TR3 from the COLLECTOR of transistor TR1, TR4 does not heat up any more, so what could be th problem sir, thanks.
Hello Kakooza, if you disconnect the base of any transistor then it will simply stop conducting which will mean the amplifier shutting down or start malfunctioning….so that's not the correct method of troubleshooting.
If you are not sure of this schematic then perhaps you can think of changing it with another more reliable one.
here's one design that was been tested by me, and I found it extremely good because it stated working instantly without any adjustments
https://www.eeweb.com/project/circuit_projects/300-watt-mosfet-real-hi-fi-power-amplifier
Hello sir well-done, since I began working with electronics, I only have one transistor amplifier I have ever constructed and worked out for me very well but it's a low voltage amplifier(35-0-35 VAC) that's why I never used it to design the other amplifier which has a supply of 85-0-85 VAC.
Therefore sir I just need your help on how to modify this circuit so that it can work on a high voltage supply and below is it's download link;
3.bp.blogspot.com/_B8Dh2WXNvg0/S7jlUBgY9yI/AAAAAAAAEPg/BekCF03Vwk8/s1600/Amplifier OCL 150 Watt.png
Hello Kakooza, you will have replace all the transistors with substitutes having voltage spec higher than 100V….also change the resistor values proportionately using the following relationship
35/85 = existing value/X
X = existing value x 85 divided by 35
X will be the new value which can be replaced for the existing value
Thanks sir, previously I didn't mention for you the transistor which is heating up but it's TR4 MJE340 but am using C4793 in place of it and Capacitors C4 & C7, am using 22uF/400V so I really don't know cause am stuck but still for transistor s TR1,TR2 & TR3 am using MJE350 respectively so which of those could be the route cause of transistor TR4 to be heating up, thanks.
Kakooza, C4793 is fine with its specifications and matches with MJE340, but it could be a duplicate one, so it's better you replace it with another one or even better if you could procure an MJE340….I am sure the problem is within this transistor or with the parts associated with its leads.
Hi Mr Swagatam, am constructing a power amplifier with a transformer of supply 85-0-85 VAC but I got certain circuits from Google where by when I constructed one of it, it failed to generate the signal to the power stage and the second one worked properly but there is one transistor which heats up whenever I give it the above supply after it's rectified& filtered & eventually the audio sound starts to change to abnormal, so really need your help because I've tried everything but I failed to notice the real cause of that problem.
"But this circuit which worked out was designed for 65-0-65 VDC but my transformer is of 85-0-85 VAC!"
THIS IS THE CIRCUIT WHICH WORKED OUT FOR ME BUT DISTURBING ME SOMEWHERE
1.bp.blogspot.com/-TpWLQNNOl8I/Vbhhmqo_RGI/AAAAAAAAV6o/CmPvlGuLKhU/s1600/socl%2Bv-5021.jpg
Hi Kakooza, sorry I cannot find anything wrong in the circuit, not sure what may be causing the issue…may be the transistor is faulty or connected properly, or its base resistor is not OK.
Hi mr swagatam thanks for reply me, dear i have required a circuit of smps 500vAc to 12vdc 2A please help me
Hi swagatam
Actually I,m interested in Mr Singonet circuits for my Dc ups,how to use this circuit to sense 220VAC and flow the current of a 12 volts battery to the load,I have to do it with mosfes,but my load is 12volt and I need to supply it whenever mains fails
My load is rated 8 amp.max,pleasr suggest me a mosfet model
Thank you again
Mr Swagatam,
thank you very much
but i need something like this :
https://drive.google.com/open?id=0B2VgP4YQwP4EaGxZak9qRXc2N00
actually i need a very simple 220 volts indicator with LED , then i wanna replace LED with a mosfet to make a electronic switch
thank you again
Mr Singonet, you can do it in the following manner:
replace the LED points with the transistor gate(base) and source(emitter)….
gate(base) will connect with the C1/D1 junction.
Replace D1 with a 12V 1 watt zener diode, connect the anode on the neutral side of the indicated mains input….remove R1 it is not required.
now connect the LED between the drain(collector) and the C1/D1 junction with a 1K resistor in series with the LED
Hi Swagatam
I'm designing a mini DC UPS , so i need to detect main failure
i need an simple circuit which switch a MOSFET ON/OFF whenever main Fails or when get back !
it should be fast enough to protect my Loads from interruption
Hi Singonet,
you can try the following concept:
https://www.homemade-circuits.com/2013/03/simple-dc-ups-circuit-for-modemrouter.html
But in my battery datasheet said :
Standby use : 13.5-13.8 volts
Cycle use : 14.4-15.0 volts
is 14v safe for standby use ??
If you are not using the battery frequently then 13.8V will be better
Thank you , for a SLA battery what charging voltage is common ?
in normal temperature(20C to 40C) 13.7 is goood ? the battery is standby and it's not on load
14V is good and will keep the battery almost fully charged, at 13.7V the battery will be only 70% charged
Thank you,so I wanted to this charger for a battery backup setup,it means I should leave my battery permanently plugged to this charger,in this situation you think my battery will be damaged even with low amperage transformer?? If yes,so please help about a simplest automatic 12 volts battery charger ,besides I have to use 16 volts transformer,
Thank you again swagatam for all your supports
You are welcome shayan!
You can try the first circuit from this example article:
https://www.homemade-circuits.com/2012/08/make-this-48v-automatic-battery-charger.html
since yours is a 12V battery, you can eliminate all the 22k resistors and the zener diode connected with pin#7 of the IC.
Rest can be used as indicated in the diagram. This circuit will always cut off the supply to the battery whenever it's fully charged and resume as soon as it drops below that level.
yes it is not safe to connect a battery continuously with a source which may be above 1/10th of its AH value….you can use the above linked circuit with your LM317 circuit to ensure a constant 14V from the 16V source.
Thank you swagatam,
With all respects manufacturer said this is trickled mode charger and you can leave you battery permanently under charger !!
Also I myself leave a 12 4.5ah with this charger for months!! How can I be sure about this subject?
Shayan, if it' a trickle charger then automatic function becomes irrelevant, and anyhow the circuit does not have an auto-cut off and it is not required if it is a trickle charger. But a trickle charger will not have the ability to charge a battery if it's discharged below its optimum level…and a trickle charge current is supposed to be at least 10 to 30 times less than the battery normal charging current, so in your diagram the circuit is designed to provide 1.3 amps…that implies your battery should be at least 100AH to be trickle charged with this charger safely.
applying 1.3 amp to a 4.5 ah is suicidal, I am not sure how your battery is surviving for months connected to this charger.
OK I think I got, it's because your charger is set at 13.75V which is much less than the optimal 14.3V….so by keeping your battery undercharged you are able to carry on with this inefficient charger… for months 🙂
https://www.homemade-circuits.com/p/lm317-calculator.html
I used 220 to 16 volts 600 milli ampere transformer,but if this charger is not automatic why stop charging after battery reaches 13.6 ?!! So strange
when a battery gets fully charged it stops accepting further charge, that's why it seems the charging has stopped.
In that case you can simply use a supply from 14V rectified source, no need of 317 and the remaining circuit, you will still find the battery cutting off at 14V.
automatic charger will completely cut-off (switch off) the output supply to the battery through a relay or a transistor on full charge which your circuit is not equipped to do.
Hi Swagatam ,
first i want to thank you for all supports you have done for me
i have a very simple automatic 12 volts battery charger which working very well
i myself draw its schematic from the real board,
i need some modifications , i would be glad if you help me and also share this circuit on your wonderful site
this is the schematic :
https://drive.google.com/open?id=0B2VgP4YQwP4EYjlIZkF2MS0xUmM
1- i need to add 2 LED's to this circuit , one for charging indicator and one for indicating battery full charge
2-when main fails or unplug (for long time) battery current comes back to the circuit and it will drain the battery , we can not use diode because circuit cant detect battery voltage so automatic behavior of the circuit wouldn't work
thank you for you time and help
Hi Shayan,
first of all this is NOT an automatic battery charger
Adding LEDs for full charge and discharge is not possible in this circuit, you will need an opamp circuit for that, without a opamp it is not possible to get an automatic operation and the indications..
as shown here:
https://www.homemade-circuits.com/2012/07/make-6v-4ah-automatic-battery-charger.html
diode can be added at the output of your circuit, no problem with that, the circuit will still detect the discharge levels, because the moment you connect the battery it will pull down the LM338 output supply to the same level, through the diode.
But I'm using this circuit from 2 year to now without any problem and it's detecting full battery and doesn't charge it,also its manufacturer said it's automatic and I,ve test it
It is working for you because you are removing the battery from the supply manually. If you keep it connected permanently then slowly your battery will get damaged with this charger, because the circuit does not have the cut-off facility or an automatic changeover from high current to a lower current level when the battery gets fully charged
batteryuniversity.com/learn/article/charging_the_lead_acid_battery
Hello
Mr. Swagatam
I hope you are in a good live.
Sir i need your help if it is possible for you.
I need a electronic circuit for that i will explain it.
I want circuit uesing transistor or ice 555.
When i press on the switch the circuit. Start counting for one minute after counting the relay turn on and stay on for 3 minutes after 3 min the relay turn off.
Remember the main switch is on.
If i switch it off and switch it on again the circuit start same cycle.
Hello Mohammad, if it's possible I'll try to publish it soon
V1 = 12V
R2 = 150K
R3 = 10 Ohms
R4 = 10 Ohms
Q
D1 = D2 = 1N4007
C3 =
T1 = 13-0-13 step up transformer
i have no transistors TIP41/42A
But i have mosfet 7805.
Can u you hlp me to build a inverter grom these components??
No, these won't be enough for an inverter
A quick response as expected! Thank you very much.
Of course you are right. I will tell you where I went wrong. I was of the opinion that the CFL circuit just needs to produce sufficient initial voltage to initiate the discharge and then the potential falls to a safe value. So doing away with that portion of the circuit would straighten out the things. It is at this point that I sought your help. What I overlooked here is that it would actually incorporate a step up circuit as well to take the value to roughly 230V to keep the discharge going and CFL illuminating. And you do not need 230V to light up LEDs'. It is much easier construct a simple circuit for auto switching and battery overcharge/deep discharge protection than to try and take out those stages mentioned earlier from an already built circuit.
P. S.: Where do you procure components for your circuits here in Mumbai from? Is it from Lamington Road?
You are welcome!
Here's one emergency lamp circuit which you can included in your existing design:
https://www.homemade-circuits.com/2013/02/make-this-automatic-10-watt-to-1000.html
Yes, in Mumbai Lamington Road is the place where you can get all kinds of spare electronic components.
Dear Mr. Majumdar,
I stumbled upon this fantastic blog of yours while looking for some circuits online and I must say your work here is praiseworthy. I used to design circuits a long time ago when help was not readily available on the click of a button and you had to depend on some magazines to share your circuits with the world. That too if they chose to publish you. You, therefore, are doing a commendable job here; helping enthusiasts and hobbyists. As it appears you are devoting quality time here, not only publishing your circuits but also helping people construct them in addition to designing circuits requested by them, I think I could ask you to help me here as well. Could you suggest a way around so that an old Emergency Light Circuit meant for 9W CFL could be used with LEDs'?
Thank you very much Knight,
If your emergency light back-up is through a battery then probably you wouldn't require the CFL circuit, because LEDs can be illuminated directly with the battery… here it would be via a relay for the required switching actions.