It's possible that this design was created with a big reserve in mind, so using heat-sinks & fuse might be overkill for the purpose.
I saw similar device (SMD PCB), where output connected to IRF8313 Power Mosfet without heat-sinks. It max total current is 5A though.
So I should use MOSFET with lower Thermal resistance junction-case RthJC value, smaller the value it is better the heat radiation.
Would be these a good substitute: Infineon [link...
Theoretically, max power is 2A x 12V = 24W per driver circuit: so I still have some power reserve?
Possibly, I can use copper area around DPAK Mosfet for heat dissipation?
For THT cdesign, would be fine to use resistors with 1/4W power rating for all elements or it need be calculated?
If use SMD design, what is common SMD resistor size (Code) that can be used here? (Imperial/ Mectric)
Yes, internal jumper, or DIP switch. DIP switch perhaps better, I need SPDT DIP Switch (ON-ON, without center position). Searched on Digikey, but still didn't find good accurate one. The line-in input is Terminal block, not 1/8" plug socket, and Mic is on board.
Could anyone suggest switch/input selector for mounting on PCB (through-hole)? Device have two inputs, Mic and Lin-in input. Capsule Micro Electret Mic Ø10mm in mounted on PCB, Mic is default input mode. When I need switch to Line-in input, I just put jumper. Or maybe some other small handy switch.
For through-hole mounting trimpots, Digikey offer 120 models for given criteria. What type is better suitable for application? does Tolerance % matter?
Normal means "for indoor use". -10C to +60C / 14F to 140F Not in aerospace industry. :)
@BrianG For myself, yes. You are absolutely right, assembling SMD PCB professionally at home is very difficult, and also requires a very sharp vision, and solid hand-soldering skills. I didn't plan to...
Is there anything else wrong in mixed technology, when use SMD + some Thru-hole components in one PCB, except more complexity and thus extra cost?
In terms of reliability?
@itsmoked Thanks for the helpful advices! Will try to follow it.
Those TO-92 transistors - 1 x FET J310 and 5 x 2N3904 is only available in TO-92 package.
Power MOSFET 27N3LH5 have DPAK SMD package, but with less Total power dissipation 30W, these Power MOSFETs drives the current (1W LED...
Its for myself, not for mass production, though. SMD PCB is much smaller and looks better. I can stay with through-hole design though, just need make new PCB a little smaller.
Design it not mine. Which terminal block model is usually used in such design for wire-to-board wiring? (commom Pitch, mm).
Yes, I looked for some SMD versions of that components. In particular, I am not sure about SMD trimmer potentiometers: although they are not intended to use it very often, they are extremelly small size 5x5mm, and seems it will be very difficult to tune/adjust it with screwdriver. What's power...
