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  1. spur

    Need some interesting usage of electronics in agriculture

    Hi, Does anyone knows some of the amazing applications of electronics in agriculture? I'll be grateful if anyone could help me find some. Of course I need some technical (or detailed) information about those applications. thanks guys.
  2. spur

    0-30V Stabilized Power Supply

    but datasheet of 1N4148(fairchild) shows that with 30mA forward current , forward bias will be 0.8V. so the negative supply will be 1.6. I think 1.5V is reasonable.  ::) BTW, can I use my 30V 5A transformer with MC34071 or TLE2141? in your part-list the transformer is characterized 28V 4.3A !!?
  3. spur

    0-30V Stabilized Power Supply

    but my transformer is 30V 5A (although I'm not sure about 5A), can I use these opamps with this transformer? the load current ( if you mean negative supply pin of U3 ) is very low, that is correct, but C3 is continuously discharging through R3 (220ohm) . with 10V across C3 the discharging...
  4. spur

    0-30V Stabilized Power Supply

    ooo! i haven't thought of that. I think I have to build the circuit and test the resistor values in real circuit. I'm having trouble finding OPA445, a friend of mine is going to buy them for me, but he will not come to me until two or three weeks later, so I have to wait  :'( thank you for your...
  5. spur

    0-30V Stabilized Power Supply

    Hi what happens if I remove R1? what if I increase the value of R2 to say 560 ohm? (in that case I can use a 1/4 watt or 1/2 watt resistor.) I simulated the circuit, the lower waveform is -1.3V line, the upper waveform is the voltage across C2. the black waveform is for R2=82ohm and the red...
  6. spur

    0-30V Stabilized Power Supply

    thanks audioguru  :) OK! here is my problem 0.7mA * 1Kohm = 0.7V , R16 shunts the base-emitter junction of Q4, so there is 0.7V across base-emitter, so the transistor turns on.  ??? am i wrong? i did a few searches over the internet and found out that Icer (a resistor between base and emitter...
  7. spur

    0-30V Stabilized Power Supply

    Hi, what is the role of R16 ?  ;D  ;D I know that it has been asked by some people before, and here is the answers: OK! but i can't get it clearly  ::)  ???  :-\ how does it bypass the leakage current? does the leakage current passing through Q4 causes the Q4 to turn off? does flowing the...
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