THT Resistor to SMD


#1

Hi everybody
This is my first forum @ contextual electronics.
I have lot of THT Resistors in my PCB project but i would like to use smd resistors .

How I can select equal values THT to SMDs…

Thanks


#2

Selecting the Ohm shouldn’t be the issue as such.

I would think the first thing to consider - not knowing anything about your project - is the power rating of the THT Resistors to at least be sure to match that for range of SMD resistors you will be looking at. Then there is the size. If you intend to be hand soldering, then you should pick a size that you are comfortable with. With those two aspects decided, then it is a matter of looking for the Ohm value in chosen ranges. If the value is not available, then you might need to check the other sizes or power ratings as well.


#3

Thanks for answering.

the voltage rate is +5V…
please note I have these values only 330Ohms, 10K ,1K and 100R nothing else.
thanks


#4

In my projects I try to use all 0805 size SMD resistors. Easy to solder by hand, but still quite small. For your 100 ohm resistor this might not work, see here:
https://www.digikey.com/products/en/resistors/chip-resistor-surface-mount/52
and select 100 ohm, and 0805 as package. Sort by price and you’ll get e.g. this one:
https://www.digikey.com/product-detail/en/yageo/RC0805JR-07100RL/311-100ARCT-ND/731185
Power rating is 0.125 W. But in case your 100 ohm resistor has a voltage drop of the full 5 V, a current of 50 mA is flowing, so it dissipates 0.25 W.
But you can search for power as well on the Digikey site. Select 100 ohm resistance, and maybe 0.5 W so that it doesn’t get too hot. Then you get e.g. this resistor:
https://www.digikey.com/product-detail/en/stackpole-electronics-inc/RNCP1206FTD100R/RNCP1206FTD100RCT-ND/2240655
Size is 1206. If you don’t need very small boards, you could buy all resistors in 1206, they are even easier to hand solder. And with 3.2 mm length not too big anyway.