Edit: fixed numbers.
No. But you'll be injured if you short it with any metallic objects while touching it, like the wiring, the board, your probe, the ring on your finger, etc.
You can short circuit using your body and you'd probably feel a tingle (your body resistance is not high, but not too low either). But if the ring you're wearing on your finger is causing the short circuit, thousands of amps will flow through it, as it has an ultra-low resistance, and heat it up to temperatures that will quickly cause burns and whatnot.
If the device does not have infinite amps, then this is the case where normally the power supply's fuse would blow, and thus the ring would never heat up and nobody would get hurt.
To summarize: Low-voltage, high-current electricity is indirectly dangerous, whereas any high voltage electricity is inherently directly dangerous.
Very high voltage with very low current is not inherently dangerous. Static electricity is this case. The total energy (voltage x current x time) passing through the body is the critical determinant of harm.
That must be true normally. But years ago I recall reading about someone who fixed an 12V underwater light in a pool. You would imagine that would be harmless, but he managed to create a circuit that ran across the pool. It was a salt water chlorinated pool, and after doing the job he dived in, and it killed him. I don't know how wide the pool was, but in any case the voltage across his body must have been less than 12V, and possibly a fraction of that.
> As my electrical safety instructor said, "The reason we now have to teach the electrical safety course to all electricians at least twice per year is because some joe was bright enough to be the one person in the world who could figure out how to kill himself with a 9V battery."
Your sweat starting to boil of your skin doesn't sound like a very pleasant way to pass the time.
Smelled awful and had a brown patch a few mm wide on my finger for a while.
This happened more or less instantaneously.
Batteries in general are fairly safe because their voltage breaks down at high loads. The chemistry can only react so fast internally and is controlled by various factors.
Contrast this with capacitors, where there is always a general safety warning when handling them in live circuits. They have no limit based on chemistry.
You don't want to test a capacitor with your tongue. A capacitor has no other current limit than it's internal resistance, with a modern sub10mOhm ISR a capacitor can, for the briefest of moments, discharge at up to 14 Kilowatts, quite the upgrade from the 14 measly watts that your spit will handle. A 100 Millifarad Low ISR Cap can sustain a kilowatt of output for almost 0.1 milliseconds, at which point you'll likely regret the choice of mishandling a cap. (It's only 14 Joules but these 14 Joules will be moving very fast)