
9-6 Sensors and Sensor Technology
on–o control circuit in the literature (as shown in Figure 9.3) [17]. e on–o controller is the
simplest form, where if the microhotplate is cooler than a set-point temperature, the heater is
tu
rned
on at ma
ximum
po
wer,
an
d
on
ce
it is ho
tter
th
an
th
e
se
t-point
te
mperature,
th
e
he
ater
is sw
itched
o co
mpletely
. Ho
wever,
ba
ng–bang
co
ntrol
ca
n
gi
ve
ri
se
to in
stability
(u
nless
co
n-
trolled
ca
refully),
wh
ich
in tu
rn
co
uld
da
mage
th
e
he
ater
du
e
to ve
ry
ra
pid
ch
anges
in vo
ltage
(h
ence
te
mperature)
.
Ba
rrettino
et al. [8
,18]
pr
oposed
a sim
ple
pr
oportional
te
mperature
co
ntroller
ci
rcuit
as sh
own
in Figure 9.4. e ...