Hi everyone,
my project is to make a robotic arm but I don’t really know what component I should buy. Can someone tell me which servo to buy, or what is a power circuit board
thanks
Hey there.
You may want to start by considering what you need the arm to do, which would then tell you how much torque you need in the servos. That will then dictate what sort of arm you would need to accommodate those servos. You could then also deduce what sort of power/battery options would work. …basically… start by thinking about the capabilities of the arm.
Let us know what you decide! 
You can get a kit, or at least some inspiration here:
robotshop.com/en/robotic-arms.html?limit=60
If you need it for a science fair or something along those lines, consider an inexpensive kit and change the mechanics.
Ex: robotshop.com/en/robotic-arm … =RB-Mea-02
Ex: robotshop.com/en/freaksarm-4 … RB-Elf-234