Sidac
Data Sheets
(a) Circuit
(b) Waveforms
V
BO
V
R
SIDAC
C
V
≥ V
B0
V
DC(IN)
C
t
t
I
C
L
R
L
I
L
V
V
- V
BO
- V
IN
BO
R
≤
max
I
IN
TM
R
≥
min
I
H (MIN)
Figure E9.15 Relaxation Oscillator Using a Sidac
Input
Voltage
tw ≈ 3 ms
VCE Monitor
(See Note A)
0 V
tw
(See Note B)
RBB1
5 V
Collector
Current
0.63 A
100 mH
100 ms
2N6127
(or equivalent)
=
150 Ω
TIP-47
Input
0
50 Ω
Sidac VBO
+
RBB2
=
IC Monitor
50 Ω
VCC = 20 V
100 Ω
-
Collector
Voltage
VBB2 =0
+
-
RS = 0.1 Ω
10 V
VBB1 =10 V
VCE(sat)
Test Circuit
Voltage and Current Waveforms
Note A: Input pulse width is increased until I
= 0.63 A.
CM
Note B: Sidac (or Diac or series of Diacs) chosen so that V is just below V
rating of transistor to be protected.
BO
CEO
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. ]
