Electronics Flashcards
What is an Optocoupler?
-Provides electrical isolation by communicating via light signals using an LED and receivers such as LDRs
-protects internal electronics from surge currents during fault conditions
Advantages of a Transistor
- Faster switching
- Silent switching
Disadvantages of a Transistor
- Can’t switch AC
- No electrical isolation
What’s the function of a ‘Snubber’ circuit
Protects voltage spikes in a Diac/Triac
Draw and label a Diode
—->I—-
A P/N K
A = anode
K = cathode
What’s a Diac used for?
- Used for triggering a device in conjunction with the capacitor and variable resistor
– triggering voltage between 28v - 36v
In relation to triacs what is meant by Zero cross over
The point in which current changes direction
What are triacs used for?
- Lamp dimming circuits
- motor speed control
- PLC output modules
- Static AC switching
- electric heating control (ceramic cookers)
Difference between triac and thyristor
- Triac conducts current in both directions
- Thyristor conducts current in forward bias
Disadvantages of Thyristor
- can’t be used for fail safe switching (e.g emergency stop
- allows current to flow in only one direction
Advantages of Thyristor
- no mechanical wear
- used to control high power applications
- Used to vary the power applied to load
What is gate trigger voltage
Signal used to switch on a Thyristor
What are the two types of operational amplifiers ?
- Inverting
- Non-inverting
Advantages of a Triac
- no mechanical wear
- full wave AC control
- used to vary power
Disadvantages of a Triac
- can’t be used for fail safe switching
- requires a triggering device such as a Diac
- Generates harmonics while firing
