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Everything posted by metal

  1. Hello I just wantes to know what is the purpose of REF HI and REF LO pins, also does the above schematic has a 2.000 volt full scale or not . In AN023 application note, it is said that to obtain 2.000 volt full scale, pin 29 cap must be 47nF, pin 28 resistor must be 470 K, and pin 27 cap must be 220nF. Is that right. I noticed that you done the opposite. Thanks
  2. Hi everybody I am designing a power supply using LM317KCS,and from the datasheet I have downloaded from TI's technical documentaions,this regulator IC is capable of delivering 1.5 Ampere @1.25 to 35 volt output,considering the condition that the voltage drop accross the IC multiplied by the consumed current does not exceed 20 watts,the power dissipation. I am using 15-0-15 volt transformer rated at 2 Ampere,and to avoid exceeding the power dissipation rated for the IC,I used a switch to select between 15 volt and 30 volt input to the IC,so when I need 10 volt output for example,I switch it to 15 volt input,but this is seriously impractical,so I tried many times "but failed" to design a circuit that senses the input-output voltage drop,and the current consuption,so that when the votage drop accross the IC exceeds 11 volt and the multiplication of both values exceeds 16.5 watts,a switching occurs from 30 volt input to 15 volts input to the IC,so that means a low voltage is needed at high current,and when I need higher voltages "say 20 volt" it automatically switches to 30 volt input. How can you help me friends,as using external current booster transistor to overcome dissipation is excluded from my options,and some times I hear a relay clicking in commercial supplies when turning the voltage wiper to higher output voltages. Best regards.
  3. Thank you for the reply I think those ICs are out of production lines these days,but the manufacturer is mitsubishi. I meant if any body got their datasheets from the old days of internet,anyway thank you for every body.
  4. Hello What happened with LM350 is as follows: As its designed to dissipate a power of 30 watts,and it can be calculated using the formula: P=V(drop)*I(consumed) So when you are using 24 volts transformer,and want 12 volts,the maximum current that you can draw is 2.5 Amp.
  5. metal

    amplifier hum

    Hi ;) The chassis may be connected to the tape head wire shielding ,so when you touch it the speakers start humming,because you form a source of 50Hz or 60Hz mains hum as you being human,and affected by electromagnetics,as antennas are,just to make the image closer.
  6. Dear Everybody :) Imade A mistake when quoted the ICs numbers,but here are the right numbers,would any one has a datasheet for them. Best regards
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