Author Topic: umiinit po.... (Read 2902 times)

subzer0 · « **Reply #20 on:** February 28, 2009, 12:17:27 AM »

ganito gawin mo,bili ka ng transformer 12 Vac rating 3amps,gawa ka ng bridge rectifier,output nyan nasa 12*1.4142 = 16.97Vdc tapos ilagay mona yung 7812 regulator
then 7805 tapos lagyan mo nalang ng series pass transistor regulator at short ckt protection diodes.may thermal shutdown naman yung regulator,lagyan mo lang heatsink para di masira agad PSU mo.

Philippine Electronics Forum · « **Reply #20 on:** February 28, 2009, 12:17:27 AM »

HexFET · « **Reply #21 on:** February 28, 2009, 07:41:58 AM »

7805 is 5v out at ang maximum current mo is 1A meaning ang kaya mo lng isupply is 5W, input mo is 12V. Diferrence ng output at input is 7V at 1A, 7W ang kelangan idissipate ng heatsink.

Ung adaptor mo na 18W 12V, iset mo po ng 7V lang para 2V lang ang difference ng input/output ng regulator mo which means at full load na 1A, 2W lang ang ididisippate ng 7805 mo.

For 7805: Set input 7V, Output is 5V. 2W dissipation for the TO220 package will maximize tab temperature so you may want to put a small heatsink on the 7805 para imaintain mo ung temp below 125 deg C at full load condition.

Hope this helps.

Philippine Electronics Forum · « **Reply #21 on:** February 28, 2009, 07:41:58 AM »

marviella · « **Reply #22 on:** March 02, 2009, 01:30:49 PM »

d po iba iba.. 2 kinds lng ng program.. yung sa 5 na slave ay parehu lng lahat.. kasi stepper lng naman.. la na po tym gumawa ng programer ng maraming pins na pic.. amp! sa 10 na defence

Philippine Electronics Forum · « **Reply #22 on:** March 02, 2009, 01:30:49 PM »

marviella · « **Reply #23 on:** March 02, 2009, 01:33:06 PM »

salamat po.. yung gnawa kong sulosyun ay pinagsama nlng ang dalawang adaptor, yung isa ay 12v at isa ay 7 v na nkaregulate sa 5.. tapos sinama mga GND nla as coomon.. my sense ba yan??

Philippine Electronics Forum · « **Reply #23 on:** March 02, 2009, 01:33:06 PM »

bravokilo · « **Reply #24 on:** March 08, 2009, 02:02:05 AM »

The 7805 is a linear VR. It is not a switching VR.so,the voltage drop accross it becomes heat. If your voltage source is high, yeas you can cascade it so that you distribute the heat among the VRs cascaded. the other parameter is your max current need from the VR. You can parallel and to make sure you will not have one VR feeding the other one when it has a higher output, use blocking diodes in series to each output of the VRs. A better way is to use a bypass transistor with the VR to raise the current. a 3055(NPN) or a 2955(PN) can be used or any equivalent TIP___ transistors. You have to put a bypass Q on all the cascaded VRs. Now the LM350 can carry a higher load. and you can adjust the output by faking the feedback on its sense terminal. So, you can cascade 3 LM350 if you can find them. there is also a TO5 317 which can handle 3A I think. By the way, if you parallel VRs and use blocking diodes, the output regulated V will be less by .7V, so use a 7806 or fake the sensed voltage by putting an R in series on the center leg and an R tothe output to create a voltage divider for the 7805 to put out 5.7V.

Philippine Electronics Forum · « **Reply #24 on:** March 08, 2009, 02:02:05 AM »

toasted siopao · « **Reply #25 on:** March 08, 2009, 08:22:49 AM »

Quote

use blocking diodes in series to each output of the VRs. A better way is to use a bypass transistor with the VR to raise the current.

Still, your blocking diode will have a drop of around 0.7V, kapag tumaas ang current demand ng load, iinit ang pass diodes mo.

This is good if your load is a fix load not varying load, anyway may mga 3A diodes naman, you can try that, pero still umiinit pa rin sila.

HexFET · « **Reply #26 on:** March 08, 2009, 11:59:53 AM »

Quote from: marviella on March 02, 2009, 01:33:06 PM

salamat po.. yung gnawa kong sulosyun ay pinagsama nlng ang dalawang adaptor, yung isa ay 12v at isa ay 7 v na nkaregulate sa 5.. tapos sinama mga GND nla as coomon.. my sense ba yan??

pakiexplain na lng po kung pano n'yo pinagsama.. kung ung ground lang ginawang common, ok lng yon... linear non-isolated naman po yan.

marviella · « **Reply #27 on:** March 12, 2009, 02:00:39 AM »

yung GND lng pngsama ko.. dalawang gnd ng dalawang adaptor..

dmhonz · « **Reply #28 on:** January 25, 2011, 04:15:58 PM »

mga sir pede ko po ba makuha schematic diagram ng bond paper vending machine nyo thanks in advance

marviella · « **Reply #29 on:** January 25, 2011, 05:29:55 PM »

Sa mga tumulong salamat pala sa lahat......
its almost a year na after natapos ang thesis na to....
succesful po e2...

MARAMING SALAMAT!!!

Philippine Electronics Forum · « **Reply #29 on:** January 25, 2011, 05:29:55 PM »

Philippine Electronics Forum