Grumblydore I suspect there is some variation depending on the manufacturer of the device being sold, and the version or age of the stock. If you buy expecting just 1 decimal place, and get 2 where the display permits it, then treat it as a bonus. Do not buy it expecting 2 decimals, unless the seller actually confirms it.

Grumblydore No, the holes on Veroboard are connected in strips, but on these prototyping boards, each hole is an isolated connection. These particular boards are double sided and through plated, meaning you have a soldering point on either side of the board. Be wary of the cheaper single sided boards, where the heat of soldering can loosen the bond between the copper and the board itself, rendering that position useless. I haven’t tried these double sided boards but they will be far more practical when connecting header pins for a plug in board for an arduino type project for example.

Grumblydore I suspect the claimed figures are a) ambitious, and b) only achievable under ideal test conditions. In the real world, pretty much all solar panels will fall short of their claimed output for a variety of reasons (angle to sun, intensity of sunlight, temperature, etc.)

Grumblydore The SIM goes in your phone or tablet. Then the watch pairs with the phone or tablet via Bluetooth. The watch itself does not have a SIM.

Grumblydore That is the voltage required to operate the unit itself, not how much the unit can measure.

Grumblydore It will display the ‘apparent’ average voltage being delivered due to PWM, but it will not display duty cycle information.

Grumblydore It is a simple voltage and current meter - you can use it in any (dc) circuit. If by ‘compatible’, you mean, is it programmable or controllable from an ESP32, then I think probably not. It is a passive device as far as I know.

Grumblydore Hit the ‘See all description’ link, and then scroll down. Connection cicuit diagram is there. However, the thin red and black wires provide low dc voltage to the meter to make it work. The thick red and black wires connect to the circuit you are monitoring, to measure voltage, while the third thin wire (may be yellow or white) connects to the load circuit and is used by the meter to calculate the current flow.

Grumblydore It works from both US 110v and rest of world 220v AC supply.

Grumblydore Click the link that says “See all description”. The connection diagrams showing how to use this tester to monitor a circuit are there. However, perhaps what you are really asking for, is a circuit diagram of the tester itself? I don’t think the manufacturer is going to give you that detail.