I have no background in electrical engineering at all, and only bought my first breadboard this week. I'm still completely new to this and just trying it out.
I'm trying do drive an 12V actuator, where flipping a switch reverses the polarity. Eventually I'll be replacing the switch with a raspberry pi, so the signal (is that what it's called?) is limited to 5V.
I've managed to create a circuit on my breadboard that does this using 2 SPDT relays (I don't have DPDTs), but this obviously isn't ideal.
My primary question is
- how do I select the transistor to replace these relays?
- Should I use FET or BJT?
- What sub-variety of transistor should they be (npn/pnp?, JFET/MOSFET?, enhancement/depletion?)
- Can This circuit be constructed more simply? i.e. with fewer components?
- Does it matter that the signal and power channels are different voltages?
- What type of transistors should a new hobbyist stock up on?
- How does one generally go about selecting a transistor for a given application. e.g. What is does the flowchart of transistor selection look like?
Diagram of functional circuit with relays. A simulation of the circuit is available here.