DN igs 2th a 
rey 22 sro) [1- 34, 224 aie a at 
Ky p? b? n=1 Qa? 
It is reasonable to assume the validity of the following identities: 
by Joonr) _ Jour) 
" Jo (a, 5) Jy (ue) 
n=1 
[43] 
Q 
, ANNG (Bath as 
n=1 
Saari [44] 
If the coating thickness shrinks to zero, the foregoing solution becomes the solution 
for the bare wire. For this case P replaces G,, a = 6, anda, is defined by 
k,a, 6 J, (a, b)=P Jo (a, 5) [45] 
In the coefficient A,, N)(8,,@) = 1 and 
gee 2a,” (P - Q) a 
no a aa ley 20 Lk ee 
ky (a,? ~ p?) G + a, e) 
i 
RESPONSE OF A CONSTANT-CURRENT COATED HOT WIRE 
TO A STEP-LIKE CHANGE IN CURRENT INPUT 
When a constant-current coated hot wire is subjected to a step-like change in current 
input, the wire response is again given by the average temperature change in the wire. The 
problem to be solved to obtain the temperature increments d, (r,t) and ¢, (r,¢) in the wire 
and coating is contained in Equation [15] by setting AP = 0 and AT, = 0. 
als ch oy 2 2 Jo (pr) 1 99, 
r 2( st) + PyOoG) ep a Gd) H Oe 
c . [47] 
od 
x22 ( zt), + Pd (a,t) =0 
