no slide title · yang berfungsi sebagai saklar elektronik ... ic v z a the circuit triggers when v...
TRANSCRIPT
Thyristor
• Thyristor: devais semikonduktor solid state
empat layer dari bahan type-n dan type-p
yang berfungsi sebagai Saklar Elektronik
• Jenis: SCR, DIAC, TRIAC
photothyristor
The silicon controlled rectifier (SCR)
Q1
Q2
Anode
Gate
Cathode
p
p
n
n
Anode
Gate
Cathode
Anode
Gate
Cathode
SCRs
• The most widely used thyristors
• Use gate triggering for turn-on instead of
breakover triggering
• Data sheets list the gate trigger voltage
(VGT) and the gate trigger current (IGT)
• Turn-off requires reducing the current to
less than the holding current (IH)
Power
supply
Protected
load
SCR crowbar to protect a load from overvoltage
The overvoltage that triggers the crowbar: VT = VZ + VGT
VT
VZ
VGT
Power
supply
Protected
load
Adding an IC amplifier to a crowbar circuit
10 kW
10 kW 10 kW
IC
VZ
A
The circuit triggers when VA exceeds VZ.
VA
Load
R1
R2C
RC snubber
A snubber network can be used to limit
the rate of voltage rise across the SCR.
Bidirectional thyristors can conduct in either direction.
Four-layer diodes
in reverse parallel
Diac
I
The silicon-controlled switch is
a low-current device.
Cathode
gate
Anode
Anode
gate
Cathode
Either gate can be used to trigger or open this device.