CHT gauge in c182p
Hi,
As far as I know CHT gauge in cessna 182 with IO 550 works with thermocouple. Some ATPL question banks as well as wikipedia say that it doesnt need external power supply to work. However last time, during alternator's vee belt malfunction when battery voltage got very low I've noticed that cht began to fall down, finally reaching zero. After recharging battery everything came back to proper values.
Could anyone tell me why CHT doesnt work without external battery power?