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smartsarath2003

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  1. Do you mean connect the tweeter,1uf cap in parallel with the main speaker
  2. Hello, I want to design a simple PC speaker, probably less than 5W. The only building blocks I have in mind is a basic pre-amplifier with op-amp and a ClassAB power amplifier that will drive a 8ohm,6W speaker. But My problem is where should I have the volume control. Is it during the pre-amplifier stage by varying gain of op-amp? Also If want to add a small tweeter, what will be the simple and best way to separate high, low frequency components? ??? Can anyone help me here please.... As this is my first audio amplifiersrelated project I appreciate any sort of help ::) Thanks Smartsarath2003
  3. Hai, I used a 10uf cap between ADj and GND. I still have the last digt of my meter gowing down, but is const after few seconds. its actually going down after conncting load then going up a bit and then slowly going down. The first bit is some thing to do with regulation, But didn't understand the second and third bits. Also I loaded it with 1A const. current load. And exactly same thing that I discribed above is happening again. In addition the regulator enters thermal shutdown ??? and the voltage drops to 0V and will be back to 24V only after power off and power on back. Any solutions to tackle this problem... I used approximately 10x5x0.2cm heat sink Thanks
  4. Hello, I built a small power supply with LM338 regulator. The problem I am facing is the output voltage going down slowly when i leave the load ON. Is this happening because of temp. I connected a load of 220R at 24V output, so it not too much current actually. Does anyone have anyidea why is this happening and how can we prevent this? ::) I checked the LM338 datasheet and its given that the Vref , Iadj goes up by temp. From this can I conclude that the variation in Iadj is more than variation in Vref and thats why the regulator is pulling its output down to maintain 1.25V. Looks li bit confusing ??? Any Help Please......................... thanks
  5. Hai, Can any one explain the function of pins27,28,29 on ICL7107. Also I still didn't get clue why the pin7, which was said catode-A is shown linked to ground in the main schematic ???. Is it supposed to be pin5(cathode-dp) for required decimal pt. Also How does the ref-hi(pin36) effects final mesurement. Can i ground it to have all my voltages(at VinHi) measured in reference to 0V. thanks
  6. The problem with IR is distance between PC and Lamp and also direct contact. They will be at upto or more than 1meter. The lamp is AC and I am intended to use high current relay. I don't know what RF frequency to use or any thing abt it. All I need is either the relay ON/Off when there is signal from my PC.I have an idea with max232 IC to get signal out of PC Actually I tried to search for RF switching devices like photo transistors. And I saw some RF transistors with 2 emitter teminals and got confused ::) Basically, when there is signal from PC , RF trasmitter has to send a signal , which should be picked up by receiver and control the high current relay. As I don't need to send vast info/data i expected it to be a simple one but looks complecated.... Any help??? Thanks
  7. Hai, I need some help regarding wireless switching application. I want to control a lamp from my PC using RF link. I have a block diagramatic idea regarding this. PCserial port -->RF transmitter --->RF receiver --> Control Ckt But the problem is all these bulinding blocks are very new to me and I never worked with them at all ???. I tried to go for IR switching but looks problamtic from the application point of view. Can any one please help mewith some basic information regarding this.... Thanks
  8. Hai, I decided to use temparature sensing to check battery is charged or not after reading energiser manual for NiMh and said thats mostly same for NiCd as well. The document is avilable at http://data.energizer.com/PDFs/nickelmetalhydride_appman.pdf They boasted that temp sensing is better and accurate way. The other methods infront of me is simple DC loading or complex AC impedance. If you have good idea plz sujjest me a simple and good method Also you said LM317 current source and battery's charging current are active for almost no time. What does that mean? The 555 timer just disconnects source for around 120msec and connects for 550msec. I done that way because I red in another article that its not good for battery to have continuous charge/discharge. So I gone for pulse charge. BD677 was used only in case I increase the charge current. any more comments/Help ??? Thanks
  9. Hai, here is my simple pulse charger. Applies 125mA charge for approximately 500mSec and no charge for 100mSec. But still to include disconnecting ckt after complete charge. I am thinking of using a thermister, to see the battery is hot enough or not and then disconnecting the charging ckt. But surprisingly the battery didn't get hot when i touched at the end. I left the charger on for about 3.5hrs(7hrs-50mA given on the 250mAh battery). I have an idea of using a transister to connect across the Capacitor of 555 timer and activate it when the battery is fully charged. Any other better ideas :o Thanks
  10. Hai, Thanks for the reply By making the charger,Iam trying to learn things. So I want to start from basics, rather than using integrated IC's..... Any ideas
  11. I also want to implement a cycle Charge-rest-discharge-rest-charge I red somwhere that this(pulse-charge) will be good method ratherthan continuous charging. The discharge cycle involves sensing the voltage of the battery by connecting a load thus by finding the battery is fully charged/not. When it is fully charged , I can disconnect the circuit. If am also thinking about using thermistors to find the temp of the battery to check the battery charged or not. But don't have any clue how I am going to implement all these without a microcontroller Thanks
  12. Hai, I want to make a small AAA battery charger. I have an idea about a const current charger using LM317. So far I decided to use a LM317 and a 555 timer . Could any one please let me know any ideas without using microcontrollers. ::) Thanks
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