You are going to need three things…
a pci to pci-e bridge adapter
a pci-e 1x to pci-e 16x cable
a pci-e device
note: all pci-e devices are compatible
note: if you only end up getting a pci-e 1x cable by accident… you can still plug a pci-e 16 device into it..
note: pci-e have bigger power requirements than pci so you will have some kind of extra power connection either to the cable or to the card or to the adapter.
application: attaching a pci-e graphics card to your pc 1x, 4x,8x,16x
application: bitcoin, litecoin, etc…
sidenote: you can install a pci-e 16x into a 1x pci-e slot via cable or direct install if you have the space…