Go Down  Topic: BT-138 and inductive loads (Read 1 time)
previous topic - next topic   Apr 25, 2013, 07:04 am Last Edit:
Apr 25, 2013, 07:07 am by lemming Reason: 1 I am looking at
turning a small 240Vac motor off and on using the circuit
described in
http://arduino.cc/forum/index.php/topic,51671.0.html which uses
a BT-138 Triac. (I will only being using two states: full on or
'full' off.)  If I was driving a DC motor (inductive load) using
a Mosfet I would need to use a diode to stop on/off spikes from
 damaging the semiconductor.  Obviously this is not possible
with an AC motor. Do I need to worry about spikes damaging the
BT-138?   You need to add a snubber circuit if you dealing with
inductive load.  The resister and capacitor in series across the
load in the first circuit is nothing but the RC snubber.
Thanks Lavan.  Do I take it form your comment "..is nothing but
the RC snubber" that you do not consider this snubber is
adequate?   No.. No.. What I meant was the RC  circuit ( .01 mfd
and 39R in series