Sukhbinder

Hi to all, hey mvs sarma i asked for a FM receiver circuit and not a FM transmitter. you are right audio guru these ics went out long ago. any ideas about ics using FFL system for tuning. i found a few like CXA1191,KA22429,TDA7000 and TDA7088. any suggestions which will be the better choice. ???

Hi guys, i'm looking for a FM receiver circuit for use with cordless microphones. any normal Fm receiver serves the purpose well but i need a dedicated receiver for my FM Mic. could any suggest any circuit with minimal components ( at least the indictors should be the least as they are the most difficult to make or find) if u can find something that uses DIP ICs then its better as i want to avoid using SMD components. the power supply requirements must be as low as possible (about 3V but can be taken up tp 9V). need it as quick as possible. thanx ;)

Anyone got info on the Siemens S4 mobile. I want to know which chip was used to send different square waves for different ringtones. thanks

thanks for your help guys, i think i'll stick to the deionised water as we have a deioniser system set up at our research lab so it will be easy for me to procure it. My inverter uses an SMPS based battery charger and is a Fuzzy logic based charger system. it has options of Normal charge at 9Amps and High Charge at 15 Amps. whish one is better, normal charge or high charge, they say that high chargeing is used if u have frequent power cuts to alloww for fast charging. in my opinion normal charge is better although it takes a longer time but the battery life and performance increases. any ideas for it ???

i just got an inverter installed. its a 800 VA system with a pure sine wave output and runs on a 12V 190Ah lead acid battery. i know that the electrolyte level has to be topped up each 2-4 months in the battery, i want to know that when adding water to the battery should i use distilled water or battery water (available at petrol stations, which i think is distilled water with some acid added). the acis content of the electrolyte must also be maintained so which is a better choice, normal distilled water or slight acidic distilled water. any other precautions and care instructions for a long life for the battery. ;)

thanks for your help hotwaterwizard, but these colours just don't seem to tally with my bipolar motor. my motor has 6 wires in 2 groups. one group has a brown,red and awhite wire, and the other has a brown,orange and a Blue wire. any guesses for this? the numbers at the back of the motor are EM-22 EPM-4207 5X-30. ???

i was able to find the two coils but i still can't make out which is A and A' and which is B and B'. i still need the colour code. i found that this motor is used in an epson EX1000 printer. maybe someone has its datasheet or the printer servcice manual ca help me out. the numbers at the back of the motor are EM-22, EPM-4207, 5X-30. does this help u identify it ???

thanks for the information :D. i'll check out the motor and post the results, maybe some one else may need it just in case. ;)

thanks for the data sheets. any idea about the stepper motor connections ???. is there any way i can find them myself by following some procedure? thanx

the ic is meant to be soldered on a PCB and not mounted on using a socket. if u are dealing with high currents use a good heatsink with it. this ic is a stepper motor driver ic or in simple ways a power device.

i need the wiring code for an EPSON EPM-4207 stepper motor. it is a 6 wire bipolar motor with 1.8 degree step. i found using goggle that it is epson stepper motor used in a its printers. it has 6 wires in 2 groups. one group has a brown,red and white wire, and the other has a brown,orange and blue wire. can any one tell me the coils corresonding to this code. i got this motor as an off the shelf item. its brnad new but just the connections are not known. i'll be using a L297 and a L298N to drive it. i was not able to find a 4 wire bipolar motor. the common wires in the epson motor are not interconnected so i think i can use it as a unipolar motor also. any body having some application notes on the L297 and L298N? thanx in advance ;)

I agree with u Trigger, the effect of RF on human's health is still not determined. with the advancement of technology, most RF communication systems are moving to the higher frequencies as they provide u with higher bandwidths. i bought a panasonic cordless phone a few days back ans even that operates in the 2.4 Ghz range. there r a number of such devices in the market and are usually sold under the name of giga set or giga range. earlier i had a casio 2000 cordless phone and it worked in the range near 4 MHz. it was a sturdy set and provided me with good service for about 5-6 yrs. newer technology surely brings in new problems with it ;)

i agree with u guys that until there is enough data one cannot predict any thing. Bluetooth is surely the thing today, u have bluetooth applications not only for mobiles but even for computers like bluetooth enabled printers and even i home audio u have bluetooth headphones which can be hooked up to a mobile phone mp3 player or a conventional audio system with a external Bluetooth transmitter. u can also set up a small area LAN using bluetooth dongles (small bluetooth Tx with connect to ur PCs USB ports) and u can access the internet using this technology. WiFi is an extension of Blue tooth which provides wireless internet access over a small area with high data transfer rates. Bluetooth was initially for a small range of 10m for mobiles. try out www.bluetooth.com

what about an IGBJT (Insulated Gate Bipolar Junction Transistor) it has the input stage of a Mosfet and the output if a BJT. so u get the high input impedance of a MOS and lower working voltages and high working temperatures of a BJT

a N channel mosfet does not have any holes ( all FET and Mosfets are unipolar devices).

zener breakdown only occurs in zener diodes with a volatge below 5-6V. above which avalanche breakdown occurs. zener beakdown occurs in highly doped semiconductor junctions where the depletion region with is very small. the breakdown occurs due to high electric field across the depletion region (E=V/w) since the depletion width w is very small the electric field is very high which leads to rupture of covalent bonds which leads to carrier generation which is a cascading effect and leads to zener breakdown. Avalance breakdown is in lightly doped junctions in which the minority carriers strike the atoms releasing more carriers and thus cascading this effect leading to avalanche break down. u can refer to some good books on semiconductors by authors like M.S.Tyagi, S.M.Sze, Ben G. Streetman. we used to study these in our graduation and masters. :D

if u r going to open up a mobile phone charger i suggest u use it for the power supply u need. most cell phone chargers can provide u with a voltage of 6-7V @500mA, which will be quite enough for ur demands. u could use normal rectifier diodes to drop the excess voltage by connecting them in series (u'll get a drop of 0.6v from each diode) since mobile phone chargers are quite cheap and are optimised for thir ussage, i suggest u use them, it more easy than building ur own. i have an ac-dc adaptor of a chinese make, it has a voltage o/p of 1.5,3,4.5,6,7.5,9 & 12V @1200mA. it uses different feed back resistors to set the voltage. ;)

Hi Morpheus, the ic u r looking for is most probably made by sanyo japan. u can check for it on the sanyo website, u can find a description for it but i doubt that u'll find the datasheet. it happens that certain components that are for OEM use donot have the datasheets available for general use. the component may be customised for the OEM company. i may be wrong, but its been the case with me, i needed the datasheet for a 3 phase motor driver used in a panasonic FDD and a power amp in a sony music system, all i could find was a description but no datasheet. try ur luck maybe u can get it on the sanyo website

A point worth thinking is that they say that cell phone radiation is harmfull for health (still a debatable topic) but what about bluetooth technology. they are advertiseing for use of bluetooth accesories like headsets for phones but do you know that bluetooth uses the spectrum of 2.4Ghz similar to the freq used by a microwave oven! :o althoughthe power is very small in a bluetooth device but what will be it effects in the long term. As the formula goes E(energy)=h(Planck's constant)*v(frequency), higher freq means higher energy. whats ur opinion? ???

i agree with audioguru., these shake lights are all gimicks. i got one and when i took it apart i found 2 3V coin cells in it that powered the LED. even if they used a rechargable type battery as the power source they would need atleast a 3.6V battery to power a white led. to charge the battery u need more than 3.6V DC. remember when u shake the torch u generated electricity but its AC (as the magnet moves in and out of the coil, thats faradays principle) so u need a rectifier to convert it to DC. but u also need to keep in mind the drop across a rectifier diode (nom. 0.6V for Si and 0.3V for Ge or Schottky) so u need an AC source of min 5V considering which the coil size will be quite large. if u use thinnner guage for the coil, u lose on the current side as the coil will give u voltage but the current will be too low to charge the battery. also since the voltage generated is directly proportional to rate of change of flux, i don't think that just by moving ur arm u can get sucha high voltage. i've heard of some using very high capacity capacitors (more than 1 Farad) which are also known as gold caps, but they are just dc to dc converter circuits which steps up the voltage from small 3V cell to charge the cap and the use it to illuminate a led. ;)

how about using some delay line circuits if u can handle them. thers are some ICs like TDA1022,SAD512,SAD512D,MN3004,SAD1024A,TDA1097,MN3011 and SAD4096. u cn produce popular effects like echo, reverb, chorus ans phasing. these are CCD audio delay line circuits. u can try them out if u like.

U could use a NJM2702 3D surround audio processor from New Japan Radio Corporation (NJRC). however u'll need to connect the line out of ur car stereo to the surround processor input an u'll need to connect an amp to processor output to drive the rear speakers. so you need more hardware. u can use a TDA1555Q audio amplifier from philips. it's in a SIL package designed for car audio purposes with an output of 2x22W. its has a BTL output so take care not to connect the speaker negative to the car's ground. >:( u can check up the datasheets for more info. ;) NJM2702.pdf TDA1557Q.pdf

try reading some earlier discs. see if reads an original disc i.e. that was not made in a cd writer. try some audio cds also. have u tried cleaning the lens? if the writer is under warranty use a lens cleaner cd (though they don't work too well). still no response i suggest u take it to the service centre as the warranty will cover the repair charges. it may be possible that the lens alignment is out or bias is not correct. the best way to clean the lens is to open the drive (do it only if the warranty has expired else u'll loose the warranty) and clean the lens lightly with a cotton ball soaked with isopropyl alcohol. its the best thing and it works for me. still no response that u will have to take it to the repairs. first check up the cost for the repairs be giving the final yes. most service centres charge u such an amount that its better to go in for a new writer (cd writers are quite cheap these days). i have an old HP writer thats about more than 6-7 yrs old and writes at a max spped of 4x. its still working but the later models have a life of 2-4 yrs. truly old is gold. ;)

thanks guys for all ur suggestions. i'm planning to get one inverter for my home, so space and weight are not much concern here. high freq inverters are surely compact in size and are more suited to portable use like for camping. also they have limited surge capacities i.e. they cannot take a surge beyond their rating. transformer inverters have a high surge rating. i was looking at a 800VA model at a manufacturers site which gave a max surge of 2400VA. since i'll be needing to mostly run fans and lights, the transformer based one will be better. can any one explain me the relation between VA and Watts. i read in my B.Sc.(H) Electronics degree that W is for DC power and VA is AC power. or more appropriately DC power= VxI and AC power=VxIxCosǿ (power factor) i read somewhere that 800VA~500W. any help here ???

what happened guys no replies. i just wanted to know that can a hugh freq inverter drive normal transformer based power supplies correctly. generally all appliances are rated at 50/60Hz. SMPS based systems may not have a problem but what about normal TV sets which generally use the line volatge as the horizontal sweep freq. the transformer based appliances may make a buzzing noise. any comments guys ???