Can someone please explain the difficulty value and how it affects mining? I see that the difficulty value can be automatically adjusted very frequently but it isn't clear to me how the difficulty value is factored into the mining algorithm.

It boils down to the higher the difficulty the more hashrate (on average) it will take to find a new block, and conversely the lower the difficulty the less hashrate (again on average) it will take to find a block.

A bit more complex explanation difficulty is to keep the emission rate of new coins being generated close to the design parameters for the coin, in this case ZCash. ZCash is specified to generate new coins at a rate of 12.5 zec (10 for miners and 2.5 for founders) approximately every 2.5 minutes, or around 7200 coins/day. Without an adjustable difficulty miners could simply point more hashpower at the coin and increase the amount of coins generated, in theory to the point all the coins could be generated in a few days. By introducing difficulty into the input parameters, a nonce is required to find the next new valid block, it can use this to automatically adjust the generation rate to stick close to the design goals.

Also check out the definition of Difficulty.

Nice writeup, but one correction: there are 576 blocks (24 per hour, 24 hours), on average, per day, so 7200 coins, not 2400.

I have corrected the mistake, thanks for pointing it out.

That's what I get for trying to do math in my head, lol.

Yes, I like to get the in-head math out of the way before I load up the pipe in the evening

So at what point in time will zcash not be profitable to mine with a gpu rig? I believe that the difficulty will double every 4 years so does that mean we have 3 years or so to mine?

how come the difficult up and down always over 1 million in 1 day???

the difficult line is always 3.5 to 4.5 then back to 3.5 around in 1 day...

it is depend on number or active miner???

The high fluctuation in price is due to farms pool hopping.

Nothing irregular and common place in this area.

GG RIP ZEC DIFFICULTY

RIP profitability to most miners