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yscheok

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  1. hai audioguru, thanks for ur info, i will try it. thanks for reply me.
  2. Hai audioguru, if i using the snubber at every mosfet to cut out the over shoot current when turn on and off the mosfet, itz can reduce the over heat?? u mean the charging and dischagrging slow will cos the mosfet heat?? Can i reduce the resistor 10K? so that the charging and discharging time will more faster and the heat will reduce. is there any way to modified the circuit so that the mosfet won't over heat?? cos i didn't have much time to change type of mosfet again. thanks for ur replying.......... :)
  3. hai audioguru, can u recommand what type of mosfet driver ic? i have try to put the diod across the the drain and source mosfet, but the result is same. if i using the snubber at every mosfet to cut out the over shoot current when turn on and off the mosfet, itz can reduce the over heat?? thanks for ur reply..... :)
  4. hai audioguru, pls help me..... still remember that H-bridge circuit that u have been modified for me........, i have test it and every thing is ok. But got 1 problem is when i doing the switching of the h-bridge circuit fast, the mosfet will over heat and burn the mosfet. i have put a heatsink for every mosfet but still very heat. If i just switch on the h-bridge circuit, the mosfet wont be over heat..... is there any way to reduce the heat so that the mosfet wont burn???
  5. hai audioguru...... :) thanks a lot and speed time with me.... :)
  6. hai...... :) itz high on resistor have to refer datasheet at RDS(on), if more higher then the speed will go slow?? did u have any recomend using what type of MOSFET? if using IRF 1405, itz can maximum the speed motor?? thanks for replying me......... :)
  7. hai...... :) u mean that gate mosfet is the capasitor, so the resistor use to control the speed of charging and discharging the for mosfet switch, m i right?? itz use the concept first order circuit ( Source free RC circuit )? and the RC="tau". when the "tau" is low, the discharging will fast. 11V/1k = 0.011A 0.011A*11V= 121mW 1/4W=250mW 250mW-121mW=129mW the resistor 1k still can hold for 129mW, it not yet over, why will hot?? if i use 100K resistor, itz better?? the switching will going very slow, m i right? if i need it swithching mosfet at maximum speed, value resistor should more smaller? how to i know the mosfet are fully on?? i need the mosfet fully on, so the my motor can receive 24V and rotate with full speed. thanks a lot for replying me...... :)
  8. hai...... :) u mean that if my supply is 12V, then to turn on the TIP127 is 10V and to turn off is 12V, m i right?? and for TIP122, it need 2 V to turn on, 0V to turn off?? itz true?? the mosfet is control by voltage, mean that we have to control the voltage to the gate mosfet to turn on and off?? how about the gate current ?? at datasheet which part i should refer?? for the bjt is control by current, mean that we have to control the current to the base bjt to turn on and off, but still need 2V to turn on and max current is 120mA, m i right?? for the voltage divider, if i use both 1k resistor, it still will get 12V. but the current will different and more higher. u using 10k resistor itz to reduce the current?? i dont know how many max current for the mosfet?? itz using 10k resistor is the max current for the mosfet?? thanks a lot for replying me... :)
  9. hai... :) u say that max of 2.5V when the collector current is 3A can turn on the TIP but previous post u say that the TIP127 needs a base voltage of about 22V to turn on and 24V to turn off. which 1 are true?? im confuse?? im not understand about the meaning voltage saturation?? how do we know the TIP whether weak or not?? itz depend to the manufacturer?? itz true Posted by: bibinjohn say MOS is voltage controlled while bjt is current controlled?? if i change TIP using mosfet, how do i mmodified the circuit?? cos i not very familiar with the mosfet. IRF 530 & 9530 the VGS is +-20V, it mean that to on the Mosfet, max voltage is the 20V?? the circuit i change the TIP to mosfet itz ok cos i use the 24V to on the mosfet?? thanks a lot for replying me..... :)
  10. hai audioguru, thanks for reply me...... :) i dont really understand that u say:" The TIP127 needs a base voltage of about 22V to turn on and 24V to turn off". from the data sheet the emitter base voltage only 5V, as i know that 5V is the max to turn the TIP, am i wrong?? from the datasheet which part i have to refer to know that how many voltage to turn on and off the transistor?? cos i always refer at the base-emitter voltage. the circuit u have modified i use the proteus proffessional 6 software to test it and it something wrong cos i didnt give any signal to microcontroller then the motor already turn on. i check back and found that itz the right 1K resistor TIP 127 that i circle have to connect to the positive 24V?? cos after i change it back that circuit are right. why resistor for the base TIP 127 still using 1k resistor?? why didnt use the 220 ohm?? and also why u put the resistor 220 at the TIP 122 to the ground?? itz want to separate the current?? if remove it, itz can?? cos need to turn the motor with full speed. from the circuit that u have been modified, itz that was fully turn on the TIP?? i mean that the motor will rotate with the full speed??? cos i really need the dc motor to rotate with the full speed of the motor. if not, how do i modified circuit so that motor rotate full speed?
  11. hai audioguru..... :) the input A & B i give it 5V and 0V to turn the TIP 125 ON at side B. or input A receive 0V and side B 5V then the TIP 125 will turn on at side A. this is my circuit H-bridge combine with the PIC controller. I saw at the datasheet that the Icm is 8A, itz max current that can support?? if the current flow more then that, what will be happen?? itz TIP will over heat?? how do i calcullate that which suitable resistor i should use?? and if i want to fully turn on the TIP, so i need to give the max base current at TIP and reduce the resistor?? just u mention that itz i sholud change the 1K resistor to 220 ohm for all the transistor TIP 122 and TIP 125? from the diagram i attach, i using the relay as the switch to give input for the input A and B, i know that switch will a bit slow then using transistor, but i dont have any idea that how to use transistor as the input. cos if i direct connect the input A and B to the PIC controller, the driver will short circuit cos the input A and B receive low. thanks lot for u answer my question.... :)
  12. hai..... i have same problem in designing the H-bridge 24V 6.4A, this is my circuit attach in below... my circuit is work already but the transistor darlington are not work fully on......why?? as audioguru say that use 1k input resistors might not give enough current to the darlington transistors for them to saturate well, so how do i change it so that the transistor well work very well?? itz reduce the resistor to 470 ohm??? or more smaller?? any 1 can help me pls....... :)
  13. the white colour is emulsion paint, the brighte white colour are not much... when use the red fillter out the the blue colour from the blue LED transmit out mean that the photo detector will receive less light?? thanks for ur help.... :)
  14. i really need u all help or u all have any idea where can find some thing like that from any webside??
  15. hai, i need some 1 that have any idea about how to build the line follwer colour sensor..... i need it to detect the white line and beside the white line are blue colour.....may u all help me?? :)
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