[SOLVED] Choosing Power supply

[waly700]

hello
i try to make a small microcontroller circuit (40pin PIC MC - Sensor -16x2 LCD)and i want to power it with 5V , i use a power supply for PC writen on it (Max 130watt, 22A in 5V) but after seconds i see led burns and also LCD contract damaged.
i use a Mobile charger with 5V 1200mA but also i didnot see it's stable.
Questions:
1-what is the best power supply i can use it?
2-how can i choose the power supply?
3-More amp in power supply is better?
4-can i use resistor to decrease current in circuit?
thank you

 

[kam1787]

sounds more like you have a problem with your circuit..........

how do you mean the mobile charger is unstable?

1 - any that has clean, stable voltage with enough current
2 - see #1
3 - only if you want to power more circuits[at the same time] or add-ons, or a circuit that needs more power
4- yes and no - yes you can but in your case it is likely counter-productive

 

[DTFT]

You will likely want something like this. Hooked up to your cell phone charger, that should keep you stable.

Also, your microcontroller will only need milliamps of current at most. 22A of current will burn that thing up, if it hasn't already. You may in fact need a new PIC, from your description.

Used reasonably, a resistor can decrease the current you're drawing, but don't rely on them to take you from 22A to microamps. Use Ohm's Law: I = V/R

 

[chuckey]

"Also, your microcontroller will only need milliamps of current at most. 22A of current will burn that thing up, if it hasn't already " This is incorrect, if the voltage is correct the current will be correct. The problem is that PC power supplies are designed for MINIMUM as well as maximum currents, out of these limits the power supplies may not work correctly.
Frank

 

[waly700]

"Also, your microcontroller will only need milliamps of current at most. 22A of current will burn that thing up, if it hasn't already " This is incorrect, if the voltage is correct the current will be correct. The problem is that PC power supplies are designed for MINIMUM as well as maximum currents, out of these limits the power supplies may not work correctly.
Frank

thank you
but this mean that if i use 22A power supply on milliamps circuit, it will be safe?and the circuit will take only the needed milliamps?

 

[chuckey]

Yes if it a conventional power supply.
Frank

 

[kam1787]

thank you
but this mean that if i use 22A power supply on milliamps circuit, it will be safe?and the circuit will take only the needed milliamps?

yes, in the same way that a 10W light only 'takes' the current it 'needs'