Sidac
Data Sheets
(a) Circuit
VBO
(b) Waveforms
R
SIDAC
V
DC(IN)
≥
V
B0
VC
t
VC
C
IL
RL
IL
Rmax
≤
VIN - VBO
IBO
VIN - VTM
IH (MIN)
t
R
min
≥
Figure E9.15 Relaxation Oscillator Using a Sidac
V
CE
Monitor
(See Note B)
R
BB1
=
150
Ω
TIP-47
100 mH
Input
Voltage
0V
5V
Collector
Current
0.63 A
0
t
w
≈
3 ms
(See Note A)
t
w
100 ms
Input
50
Ω
2N6127
(or equivalent)
50
Ω
R
BB2
=
100
Ω
+ V
BB2
=0
+
V
CC
= 20 V
-
R
S
= 0.1
Ω
I
C
Monitor
Sidac V
BO
Collector
Voltage
10 V
V
CE(sat)
V
BB1
=10 V
-
Test Circuit
Voltage and Current Waveforms
Note A: Input pulse width is increased until I
CM
= 0.63 A.
Note B: Sidac (or Diac or series of Diacs) chosen so that V
BO
is just below V
CEO
rating of transistor to be protected.
The Sidac (or Diac) eliminates a reverse breakdown of the transistor in inductive switching circuits where otherwise the
transistor could be destroyed.
Figure E9.16 Sidac Added to Protect Transistor for Typical Transistor Inductive Load Switching Requirements
6
SUNTAC [ SUNTAC ELECTRONIC CORP. ]
