12volt 2.3ah battery convert to 5volt(need a circuit diagram)

[shamito88]

need help in converting 12volt 2.3ah acid battery to 5volt. I have already try to lookup some information in internet and make some test. it manage to get 5volt using lm7805 ic and some capacitors but when connect to MCU it drop to 2volt reading,... need some help get the actuall capacitor and resistor for dc to dc converter

 

[tpetar]

You must use capacitors :




If you need stronger use 78S05 its 2A

 

[shamito88]

i have already try the schematic given by the datasheet... get the output.. but after attach to MCU its drop to 2volt..

 

[tpetar]

This is not problem with 7805 then!!!!

Show circuit.

 

[shamito88]

this is my MCU circuit.

 

[tpetar]

need help in converting 12volt 2.3ah acid battery to 5volt. I have already try to lookup some information in internet and make some test. it manage to get 5volt using lm7805 ic and some capacitors but when connect to MCU it drop to 2volt reading,... need some help get the actuall capacitor and resistor for dc to dc converter

I dont understand your question about 12V Lead Acid battery and your circuit with LPT port.

What you try to make with this circuit? And where is lead acid battery?

 

[shamito88]

for your information.,, i attach the battery direct to the 12dc input panel volt

 

[ALERTLINKS]

Is your battery oK, charged? Test voltage on battery with load also.

 

[Tipu606]

how is the 12V battery getting charged?
For battery test connect any 12V car headlight bulb to the positive and negative terminals with a piece of wire and see if the bulb lights up fully, if it does then the battery is all right and then the problem of low voltage output may be else where

 

[tpetar]

for your information.,, i attach the battery direct to the 12dc input panel volt

You should put and 100nF after 7805, that will eliminate ripple. An always add one 100nF closes as possible to +/- of uC.

Check battery then, that battery is not good, 7805 can go under 5V!!!!!!! 7805 have internal protection, for overcurrent and thermal.

You need input from battery at least 7,5-8V !!!!!!

You didnt show that battery on circuit!

Dont try to charge that battery from LPT port!

 

[shamito88]

my battery is 12volt 2.3ah... i have already check with multimeter its in good condition....

---------- Post added at 22:13 ---------- Previous post was at 22:11 ----------

or its probably come from my MCU programmer board?

 

[nmbg011]

You cant get 2V from 12V battery if battery is good. Look for short circuit, check 7805 regulator without rest of circuit.

 

[shamito88]

so what you recommend me to do... buy a new or its have another way?

 

[ALERTLINKS]

Check output voltage without load. Then increase load. Regulator may be damaged. Use series resistor like 10 ohm on input side to limit current in accidental short circuit.

 

[shamito88]

i have buying a new regulator... but its still have drop voltage value in my MCU on programmer board... but when i put MCU on a test board i dont have any reading output...

 

[wjvictor]

your hand touch the regulator when operation,if very hot ,please check cpu and board, maybe find out fault.
hope help you.

 

[Ogu Reginald]

It can also be possible that either the microcontroller or some other component on the board is shorting the voltage.

It can also be that two tracks are unneccessarily touching each other, please check well.