5v feed

[msknight]

In all the pictures I'm seeing of power draw, people seem to be attaching to everywhere other than the power regulator. I was wondering why please.

I'm faced with powering the PiZero (220mA) and also the Wespi (I think about 200-300) and I was wondering where, on the board, I should put them.

The obvious solution for me, as I'm putting in a new case, is on the top of the board rather than beneath, and the obvious place to someone like me, is to attach to the power regulator pins. Or possibly the traces on the edge connector.

Grateful for any learning that people can offer please.

[msknight]

For reference, this is how far I've got. I've also checked the studs and they aren't conductive. The Wespi will go underneath the keyboard and I've got to wait for Retrolium.co.uk to open again so I can get replacement power regulators ... and don't ask me what the case is, because it's a nightmare. Wish I'd gone for something a little larger.

[Lardo Boffin]

In all the pictures I'm seeing of power draw, people seem to be attaching to everywhere other than the power regulator. I was wondering why please.

A question that has been at the back of my mind for a while. I’ve always assumed it didn’t really matter and people went for convenience?

[1024MAK]

Best place to pick up a +5V supply on a ZX81 or TS1000

Best place to pick up a +5V supply on a ZX81 or TS1000

Mark

[msknight]

:Thumbs up:

[Paul]

Best place is really close to 5he regulator and Marks place is really the best.
The Pi Zero is fine with the 5V coming from the regulator as is has sufficient filters.
The Wespi circuit shows an electrolyte capacitor and please don't skip that. It's really necessary.

[sP1d3r]

I'd have thought that the overuling consideration with the power supply would be whether the mains transformer can supply sufficient power to the regulator.
I don't know what the capability of Sinclair mains transformers is.
The power supply I use for my ZX81 can supply max 1500mA, it's a type that are commonly available and it comes with various plugs.

[1024MAK]

Discussed before in these two topics here and here.

Assuming a DC/DC converter or switching regulator is used that has an efficiency rating of at least 85%:

With a Sinclair UK700 9V PSU (rated at 700mA, 0.7A), then a maximum of 1A at 5V is available from the DC/DC converter or switching regulator.

With a Sinclair UK1200 9V PSU (rated at 1200mA, 1.2A), then a maximum of 1.8A at 5V is available from the DC/DC converter or switching regulator.

With a Sinclair UK1400 9V PSU (normally used with a ZX Spectrum, rated at 1400mA, 1.4A), then a maximum of 2.1A at 5V is available from the DC/DC converter or switching regulator.

Please note, all 5V current values have been rounded down. It's not recommended to run the PSUs continuously at their maximum power / current ratings.

Mark