[SOLVED] Need help to select a suitable SMPS

[ADGAN]

Hi! I thought of using a power supply by deconstructing a Switched mode power supply adapter for a project I'm doing without using a transformer power supply. Is it possible to do this? How do I calculate the current required by the system? My project consist of a PIC, 4 relays, DS1307 IC, LCD, PIR sensor and a TC35 GSM modem. Is 12V 1A power supply going to be sufficient for this?

 

[D.A.(Tony)Stewart]

You would be better off using PC PSU with 12V or a universal laptop charger with adjustable Vout and an LDO if necessary

 

[ADGAN]

I don't have a PC PSU. But switch mode power supply adapters are available in the local market.

 

[kam1787]

You can find out from the datasheets the maximum current drain for PIC, DS1307 IC, and a TC35 GSM modem
These don't need much current LCD, PIR sensor
Big unknown are the relays, and how many will turn on at the same time. Often relays/motors/solenoids have a high inrush current. You might want a separate power supply for them, or isolate the power supply.

 

[ADGAN]

Thank you. I'm actually using a 4 channel relay module. So does that mean its not recommended to use a Switch mode power supply for this purpose?

 

[kam1787]

Thank you. I'm actually using a 4 channel relay module. So does that mean its not recommended to use a Switch mode power supply for this purpose?

'Any' power supply will work, as long as it can supply sufficient current at the required voltage

 

[ADGAN]

Thank you!