hi all i have a circuit that works ok but i would like to modify it a little so need some help i have included the scamat.
i want to replace the leds with a transistor ??? to make them switch 12v 500ma so i can add replace led with smd led strip pic attached
can any one help
thanks

 

For switching that much juice you should use MOSFETs, eg. N type rated to 2A or higher. Ground the "source" pins and connect the low side of your loads to the "drains". The high side of the load is connected to +v. The gates are like the base of a transistor and connect to your controller. Finally, you may need to pull the gate up or down with a 1-10k resistor if the controller is not doing that.

 

any suggestions on the mosfet ?

 

search for logic level FET's

 

i have some irf530's will they do the job

 

www.alldatasheet.com
will help you to get the data u need

and no, that ain't a logic level FET

 

i have some irf530's will they do the job

You want logic level FETs so that they are fully on - almost no resistance = no heat generation - when the gate goes to +5v.

A regular FET needs ~10v to go full on, and thus will show some resistance, voltage drop and heat generation at only 5v. However it'll be "nearly" on and would probably work. Half an amp probably wouldn't cook it too fast, and you could use a resistor to adjust the LED brightness to compensate for voltage drop. Maybe try one (530) with a heat sink and see how it goes. If you're patient, go ahead and get a logic level FET.

 

Overkill, but I'm getting ready to use one of these in circuit:
http://www.nxp.com/documents/data_sheet/PSMN2R0-30PL.pdf

 

would a IRL320 or a IRLZ14PBF or evan this one witch sounds better IRLZ34NPBF
do the job just been surfing the net ??

 

would a IRL320 or a IRLZ14PBF or evan this one witch sounds better IRLZ34NPBF
do the job just been surfing the net ??

I think they will suffice as Vgs rating given is around 4.5V & 5V
If you have it, try it. But be careful of heat dissipation.
If the MOSFET get's too hot to touch, mount it on a heatsink and try again.
If the heatsink get's too hot to touch then try a bigger one

 

my brother has some IRL3202PBF would they be better
Max Voltage Vds:20V; On State Resistance:16mohm; Rds Measurement Voltage:7V; Max
thanks

 

my brother has some IRL3202PBF would they be better
Max Voltage Vds:20V; On State Resistance:16mohm; Rds Measurement Voltage:7V; Max
thanks

this will definitely do ur job. But do keep in mind the heat generated

 

circuit as this ??

 

circuit as this ??

Don't use 10KΩ for gate R, Use a value between 47Ω to 100Ω

FET gate needs to charge quickly to turn on. Don't worry uC can handle fet gate currents