Recent content by Shahriar

  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

    Dear Hero Yeahhhh, Thats right  ;D it has a Power factor corection module that boost the voltage to 424V for the main PSU. It is made by MC33262P Controller. I Had never seen such PFC circuitry before. That was nice experience! This is the Topology I thought: and this is what it really was...
  3. 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...
  4. 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...
  5. 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
  6. Shahriar

    Balance Microphone amplifier

    So what is the solution? It is impossible to mount the mic somewhere else; we can change the mic, we can change the circuits but we can NOT attach a mic to the doctor! What would you do if want to design such circuit? thanX shahriar
  7. Shahriar

    Balance Microphone amplifier

    Yeah Now that you are saying, the problem is the mic is too far away from the voices so that the sound is mostly echoes; just those part of sound which is louder can be heard; the distance between the electret mic and doctor is about 2-3m Should we add an AGC circuit? ThanX Shahriar
  8. 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...
  9. Shahriar

    Are these two circuits equal?

    Hi I didn't know there are such regulators on the market! ::) I will definitely use them in future thanX Shahriar
  10. Shahriar

    Are these two circuits equal?

    Dear audioguru when you are to power an MCU based or a sensitive device from an iginition power supply, i.e. when connecting your circuit to a Car, because of high transient voltage (upto 60v) you can not just use 7805 and some capacitors; if you search between the car CD players you can...
  11. Shahriar

    Are these two circuits equal?

    Dear audioguru Ok, put two caps around the regulator; Not important for this question!  ;) I just mean what would happen for the output if we change the Inductors position? ThanX shahriar
  12. 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
  13. Shahriar

    Redesign Elektor gigant2000 Amplifier

    Can You give few examples of resistors you believe to be calculated again except those I Said. ThanX Shahriar
  14. Shahriar

    Redesign Elektor gigant2000 Amplifier

    ThanK you for your reply and your calculation. I Think It is because of our different explanations of Class A. Can You help me to Lower the output of this Power amplifier. Tell me If I am right: I want to decrease The 78V regulated supply to 30V and 70V Unregulated to 25V. (I have a 3-way ...
  15. Shahriar

    Redesign Elektor gigant2000 Amplifier

    90mA quiescent current for each Transistor is not Low. It is said that when your Amplifier is playing, Try to Increase Bias current to convert it from Class AB to Class A, Then You will Understand the difference in Details! I have just heard it, Not tested. But I think It is really depending...
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