WHITES TDI PRO CURRENT CONSUMPTION

[Qiaozhi]

I don't think the TDI's peak coil current would be 5A.

Assuming a 14v supply, coil L = 300uH, total coil circuit R = 0.6 ohms then a 50usec pulse would only give 2.22A peak coil current. We would need a 120usec pulse to get 5A.

If the TDI had the same total coil circuit R as the GS4 (~6.25 ohms) then the 50 usec pulse would only give 1.45A and the 120 usec pulse would drop to 2A.

The pulse current on the TDI is probably not as high as 5A. That was a worst-case estimate. If we knew the TX pulse width, the coil resistance and the value of any series resistor, it would be possible to calculate the true value of the current pulse. Also, we don't know how much current is being consumed by the rest of the electronics.

[Skippy]

Dave: It's good to obtain a selection of coins for testing, particularly US ones, as they are commonly used: copper 1 cent (pre-1982?), modern 'clad' 10 cent (dime), 'clad' 25 cent (quarter), plus a 5 c 'nickel'. Also a 1 Euro. Amongst the British coins worth obtaining if you haven't got them, are Sterling silver 3d and 6d. The 3d is a tricky target, and is also a very close match to a US half-dime (5 cent) coin. The 6d is pretty close to a US silver dime, (it's a touch bigger) which is often used as a test coin by the US guys.
I asked around friends, etc, and managed to get a selection of US/Euro/ other foreign coins for free, and a few others were picked up at car boot sales (outdoor flea markets) including a silver US quarter-dollar for 20 pence.

[daverave]

Dave: It's good to obtain a selection of coins for testing, particularly US ones, as they are commonly used: copper 1 cent (pre-1982?), modern 'clad' 10 cent (dime), 'clad' 25 cent (quarter), plus a 5 c 'nickel'. Also a 1 Euro. Amongst the British coins worth obtaining if you haven't got them, are Sterling silver 3d and 6d. The 3d is a tricky target, and is also a very close match to a US half-dime (5 cent) coin. The 6d is pretty close to a US silver dime, (it's a touch bigger) which is often used as a test coin by the US guys.
I asked around friends, etc, and managed to get a selection of US/Euro/ other foreign coins for free, and a few others were picked up at car boot sales (outdoor flea markets) including a silver US quarter-dollar for 20 pence.

i have just tested my surf pi using a US 5c buffalo nickel coin and im getting around 16" in air depth...not sure if thats good or not !!!

[sinclairuser]

skippy is spot on about the thruppenny bit(old ones, sterling or 50%not the hideous brass things like the new pound coin).
i have two for testing, a 1919 georgev .925, and 1925 georgev aussie.500(mint), they make excellent setup objects.