When current go through, some conductive materials will also turn warm or even hot, so I tried different kinds of materials and look for a best which can make a heating pad.
The red paper will turn white when it feels hot.
1.conductive thread knitting mit common thread.
resistance : about 11 Ω
when voltage is 4V , current is 0.4A :
it seems like nothing happened.
when voltage is 7.5V, current is 0.8A :
it turns warm.
when voltage is 7.8V, current is 1A :
it is getting warmer.
when voltage is 9.3V, current is 1.2A:
now it’s hot.
when voltage is 10.6V, current is 1.4A:
now it is quite hot and even fast get burned…
2.copper fabric
resistance : about 0.2 Ω
when voltage is 3.2V, current 3.2A, namely the most amount:
nothing happened but the crocodile is quite hot.
3.stainless still thread.
resistance : about 7 Ω
when voltage is1.8V, current 1A,
it gets hot quite fast.
4. carbon paper
resistance : about 1 kΩ
I put the highest amount but nothing happened.
5. carbon fabric
resistance : about 0.7mΩ
the same result with No.4
6.Conductive yarn
resistance : 10cm about 1.5mΩ
when Voltage 8V current 0.1A:
Voltage 10V Current 0.15A:
Voltage 12 V Current 0.18A :
it shrinks and burns….