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  1. Shahriar

    Detection sesnor used in commercial photoelectric sensor?

    Hi Does anybody know what kind of sensor (photo diode) manufacturer uses in Red light photo electric sensor?  Specially receiver? I have found BPW34, but think manufacturers uses something else. Look at this through beam from Optex...
  2. Shahriar

    424V on Bulk Capacitor Problem

    Hi I am somehow familiar with SMPS troubleshooting; But today I have encountered a strange problem It is 48v, 150W SMPS with UC2844 Controller. The first problem was the output was low (around 42V) I Replaced the 47uF on Vcc pin of the UC2844 and everything got OK But still a small Vizz Sound...
  3. Shahriar

    Can Anybody guess how these Swimming touchPads work?

    Hi Today I saw these Swimming competition touchpads Manual (Attached file) and I am wondering how these touchpads work! it the Manual it has written :"The touchpads use a proven design incorporating three conductive plates made of  non-corrosive stainless steel to provide years of reliable...
  4. Shahriar

    What is this Capacitor Between Hot and Cold Chassis for?

    Hi I have attached a valuable SMPS Design with TEA1507 Controller; Can anybody tell what do those C5=2.2nF, R4,R5=4M7 do there? (Page 26, In the Main Circuit diagram) ThanX in advance Shahiar 66B6002Cd01.pdf
  5. Shahriar

    Balance Microphone amplifier

    Hi I am working in an hospital. there we have a room where doctors are isolated from nurses because of the X-ray. But sometimes doctors should talk to nurses. this is done by a small condenser Microphone mounted on the ceiling (On Top of the doctor head) and a pair of PC speakers in the nurses...
  6. Shahriar

    Are these two circuits equal?

    Hi Are the outputs of these two circuits different or they are the same if Vin is 12VDC with some noises (i.e. from an Ignition Motor) L1 and L2 are completely seperate and wounded on different cores! ThanX Shahriar
  7. Shahriar

    Redesign Elektor gigant2000 Amplifier

    Hi I Love Accuphase Amplifier topology very much and it is long time I am trying to find a good schematic. I found Elektor gigant2000 design very similar to Accuphase. But I Need a Lower power Design. Can Anybody tell me how is possible to redesign it for 50 to 60Watt. I Know some what to do...
  8. Shahriar

    Replacing IGBTs with BJTs in Elektor IGBT design!

    Hi I read Reviews about IGBTs, MosFETs and BJTs uses in Audio Power amplifiers. I want to build the Elektor 50W Compact AF IGBT power amplifier. I want to replace IGBTs with BJTs. I have two questions: 1- which components should I change? 2- What is the best BJT to use? (part Number) P.S. I...
  9. Shahriar

    Use your windows as speakers

    Look At this Device It looks nice and Funny http://junkies.wordpress.com/ Shahriar
  10. Shahriar

    OPA2134 Vs NE5532

    Hi I am building a 3-way active cross over circuit. the design is based on opa2134 Dual OpAmp Which has a THD=0.00008% but in my area I can't find OPA2134. I want to use NE5532 instead. But I couldn't find anything about NE5532 THD in Datasheet. Does anybody know how much is NE5532 THD. ThanX...
  11. Shahriar

    Accuphase Power Amplifier Upgrade!

    Hi I have found this Old Accuphase Amplifier schematic from a service manual website. I have also found a Manual for one of the newest Accuphase Product which has a differential input. In this manual you can find a circuit diagram without details. If you compare these two schematics you can...
  12. Shahriar

    Choosing Loud Speaker

    Hi I want to build a Big, High quality Loud Speaker But I do not Know how to choose a high quality speaker for it. I mean How can I determine if a speaker is good or not? Choose it by model? (JVC, Pioneer, ...) choosing by magnet? choosing by diaphragm meterial? How? ThanX in advance Shahriar
  13. Shahriar

    Question about this Loud Speaker

    Hi Look at this LoudSpeaker http://www.roundsound.com/reference-3-speakers.htm Two Things are dark to me: 1- Is the back of those Speakers Open or Closed. Specially the Woofer? If they are closed, Are they sorrounded with the Round Cabinet or there is a air way between the cabinet and The...
  14. Shahriar

    Project Motorola Hi-Fi Amplifier

    Hi I was Looking in Audio Project section and I encountered with this Project (Motorola Hi-Fi Power Amplifier) http://www.electronics-lab.com/projects/audio/041/index.html Something is strang to me. The output voltage is always equal to OpAmp Output. The Maximum output Swing for Opamp is limited...
  15. Shahriar

    How to build a Hall Audio system!

    Hi I want to build a system for a big Hall. If I use a usual 2-Speaker cd-Players and at one end of the Hall, People dancing at the other end of hall, do not receive enough power. What is the best topology to use. I mean How many speakers? Where to put them? and ... (what Topology they use in...
  16. Shahriar

    Look at this current mode Power amplifier!

    Hi I have designed this power amplifier. I think it is a little bit different with Normal PA, because I have tried to use two Voltage-Current converter to drive power output transistors to reduce zero-crossing. I have attached the schematic to tell me anything wrong about the topology I have...
  17. Shahriar

    Look at the link below, Some interestings with this guy!

    Hi I found this link amazing. Hope U like it. http://www.inventgeek.com/default.aspx Shahriar
  18. Shahriar

    LCD Monitor training document!

    Hi I am new to LCD monitors (but Have lots of experience with CRTs) and I want to take my skills to the next level. I would apreciate it if You could guide me through some training documents to start LCD Monitors diagnostics. ThanX in advance Shahriar
  19. Shahriar

    Help me download this Plasma Training manual

    Hi One of my friend has uploaded a Plasma TV training document for me to a free site. But unfortunately the damn proxy-serverds do not let me download it. I will apprecaite it If anyboady could download it and Upload it some where or email it to me. It will expire within 6 days. here the...
  20. Shahriar

    Plasma TV training document

    Hi I want to know if anybody has any Plasma circuit description document or any Plasma training document. or any link to download. There are lots of service manuals on th web but as U know there isn't any circuit description in service manuals. ThanX Shahriar
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