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  1. M

    SMD COLOUR CODES

    Hi, try here for alphaneumeric codes. http://www.tkb-4u.com/code/smdcode/indexsmdcode.php reg color codes, i feel normal codes do work with smd even if used however, the manufacturer concered can be googled for specific needs Sarma
  2. M

    Question: Can computer burn your house down?

    Please accept the truth-- any malfunctioning equipment -- need not be electronics or computer related-- CAN BURN A HOUSE DOWN-- FOR EXAMPLE GAS STOVE WITH LEAKING HOSE or with a forgotten open valve STOCKED ETHENOL OR PETROL IN NON-STANDARD FASION UNCHECKED ELECTRICALL HEAVY DUTY SOCKETS AND...
  3. M

    How to know the ratio of a burnt transformer?

    It is OK. do you find regulators inside or voltage stabilisation using zenor diodes? f so what is / are the regulator(s) / zenors used? Incidentally you never indicated the make and model Number of the equipment under reference. perhaps a replacement Tranformer is much cheaper compared to...
  4. M

    How to know the ratio of a burnt transformer?

    Basically you may have to study the other circuitry and the audio eqpt specification from the user manual. 1. whether input is 230 or 110V-- depends on your location. 2. you have two options. a. get it wound as it is by a local winding shop/repairer. b. do it yourself. If option is (b) , ...
  5. M

    Vacuum Fluorescent Tube driver

    Hi, Why not try ULN2003 or ULN 2803 interface chips instead of discrete transistors. Sarma
  6. M

    120VAC to a2VDC 30A power supply circuit needed

    Case.1 You try TRIAC control on primary with ofcourse suitable line filteres to meet local regulatory needs. then see that the output is stepped down to 12V. I feel this concept should serve your needs. Case2: you try to have halfwave rectification and try to regulate with nominal filter...
  7. M

    SMPS question...

    perhaps one may not call it smps, but Triac (primary comtolled) AC-DCconvertes are not unpopular. may be the type of technology was used for battery charging. Sarma
  8. M

    I like to find someone to build prototypes

    Hi Danny, Now adays experts of your status, should, ifeel, not confine to a cornerof software-- for example, i know of my co-brother whis a doctorate in chemical technology and equally good in electronic software and even hardware. Medical professionals are practicing not only medicine but also...
  9. M

    Please provide "Art-Work" or PCB Design Software.

    Aniruddha may appreciate that auto routing is NOT that effective unless the placement is opimum and the the software is really a wothy type. But again such items are obviouly priced HIGH and perhaps only High volue users and Idustries only can afford. One must accept that there is nothing to...
  10. M

    Voltage Level shifting

    you didn't mention how much current you want to draw at 5V --neither you mentioned whether it is DC or AC-- i if Dc you want large currents  use 7805 with adequate Hestsink. if dc and for very small currents like less than 5 mA use a high watt (2watts)resistor of say220 ohms and a 2 watt zenor...
  11. M

    Please provide "Art-Work" or PCB Design Software.

    Hi Aniruddha, Didi you try PCB123 .it is really nice. the software provider gets you the pcbs made as you order on him-- easy to learn-downloaduser manual it is not a demo version. you canpurchease as you need it try download here http://www.pcb123.com/pcb123download.php
  12. M

    This site is very slow lately

  13. M

    SN84LS123

    Hi Hotwaterwizard, the site is showing the devises sn84 series-- no doubt other sites like alldatasheet etc are dumb on these. however, may be, recently introduced. any other info and how they differ from normal 74 series-- any enlightenment possible? Regards Sarma
  14. M

    smps of tv..

    Hi, i didn'tmean disconnect all sec connectios of smps tfmr. i only said that the load , i mean, the DC load on 20V output-- if there is a short in the load , this type of sound comes. I was asking you to test smps exclusively with an artificial load, say two 12Volt bulbs, in series to make 24...
  15. M

    Hearing aid circuit

  16. M

    smps of tv..

    Hi should we now feel that the fuse is not blowing after second time soldering? coming to smps tranformers, the parameter to be checked is inuctance of the primary and secondary coils, turns ratio (Np and Ns, and cross insulation of secondary wrt primary. as you switch the rectified DC using a...
  17. M

    Hearing aid circuit

    Hi Walid, these are my feelings with my limited knowledge. the circuit should work from a supply down upto 1.8V (2*0.9V) where after the batteries are to be replaced. perhpas you have to maintain the overall gain of the device in the battery supply range. 10k may work well atlower voltage,but...
  18. M

    smps of tv..

    Hi Try disconnect the load and give artificail load of say 1amp across 20V point and see-- load like 22 ohms 20 watts resistor BE VEY CAREFUL AND GUARD YOUR GOOD HEALTH-- THESE SMPSs are SHOCK prone.
  19. M

    telephone transmitter again not working??

    Hi. check the PIN out data for the replaced components-- whether this aspect istaken care while soldering them? what are the voltages measuredt at the respectiveTransistors?
  20. M

    OVER-/UNDER-VOLTAGE PROTECTION CIRCUIT ANALYSIS

    Hi walid zee, High voltages cause insulation breakdown and low voltages cause high currents and heat up the device to burn. regards Sarma
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