I wanted a softstart which would be simple and compact. Just an 1-2 second delay and the ability to use a small switch as on-off switch. Nothing more.
I also wanted proper separation of high-low voltage, wide tracks, no exposed 230V at the top of the board.
So I've drawn a small (6*9cm) pcb for it. Nothing special, 230V-16A relays powered by a small encapsulated smps. The big red areas are just a reminder of the distance to keep free.
Any mistake to correct ?
I also wanted proper separation of high-low voltage, wide tracks, no exposed 230V at the top of the board.
So I've drawn a small (6*9cm) pcb for it. Nothing special, 230V-16A relays powered by a small encapsulated smps. The big red areas are just a reminder of the distance to keep free.
Any mistake to correct ?
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Old'n'Cranky: two reasons mostly. AndrewT at some point mentioned that lower value resistors have thicker wire inside, making them more tolerant to big surges. And the second reason is that I can replace them with NTC if desired, which have to be in serie.
The higher surge rating for resistors under 50R can be seen in this datasheet for example: https://www.mouser.com/ds/2/303/res_tww_twm-1228653.pdf (10x vs 5x). In this serie, resistors above 50r aren't really wirewound anymore.
And the dissipation per resistor is the same in both case. Isn't the surge rating rated in W rather than A ?
ctrlx: yes, that's even simpler but then I'm loosing the ability to use a small switch to switch on the amp.
The higher surge rating for resistors under 50R can be seen in this datasheet for example: https://www.mouser.com/ds/2/303/res_tww_twm-1228653.pdf (10x vs 5x). In this serie, resistors above 50r aren't really wirewound anymore.
And the dissipation per resistor is the same in both case. Isn't the surge rating rated in W rather than A ?
ctrlx: yes, that's even simpler but then I'm loosing the ability to use a small switch to switch on the amp.
Yes, a single sided PCB is indeed possible and could be done at home.
However, I plan on using a professional dual sided anyway. The reasons are:
- it's the same price from Chinese small fabs for single or dual sided
- with a dual sided PCB, you get more solid plated through hole connections
- while a soldermask isn't a real insulation, it is still a small further protection
And since I've got two layers, I might as well use them to increase distance between tracks. In fact I might as well put all the low voltage tracks on top.
However, I plan on using a professional dual sided anyway. The reasons are:
- it's the same price from Chinese small fabs for single or dual sided
- with a dual sided PCB, you get more solid plated through hole connections
- while a soldermask isn't a real insulation, it is still a small further protection
And since I've got two layers, I might as well use them to increase distance between tracks. In fact I might as well put all the low voltage tracks on top.
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