To Plot V-I Characteristic of Triac

Aim

To plot V-I characteristic of Triac.

Apparatus Required:

Power supply, Triac characteristics kit, Connecting leads, Ammeter & Voltmeter.

Theory:

The Triac is a three terminal AC switch that is triggered into conduction when a low energy signal is applied to its gate terminal. The TRIAC conducts in either direction when turned on either a positive or negative gate signal triggers it into conduction. Thus, the TRIAC is a three terminals, four layer bidirectional semiconductor device that5 controls ac power. Because of its bidirectional conduction property, the TRIAC is widely used in the field of power electronics for control purpose.

Circuit Diagram:

Procedure:

1. Make connection as per the circuit diagram.
2. Apply +ve supply to the circuit.
3. Increase the voltage step by step & note down the corresponding current values.
4. After a certain voltage, the Triac enters into the negative resistance region.
5. Now apply reserve polarity & repeat the whole procedure again.

Observation Table:

Graph:

Result:The characteristic of TRIAC have been plotted.

Precaution:

1. Always connect the voltmeter in parallel & ammeter in series.
2. Connection should be proper & tight.
3. Switch ‘on’ the supply after completing the circuit.
4. DC supply should be increased slowly in steps.
5. Reading of voltmeter & ammeter should be accurate.

Quiz/Answers:

Q1:Conduction take place in triac is bidirectional or unidirectional?

A1:Bidirectional.

Q2:Expanded form of the word abbreviated TRIAC ?

A2:Triode and AC.

Q3:Name three terminal of Triac?

A3:Main Terminal 1(MT1) ,Main Terminal 2 (MT2) and Gate ‘G’.

Q4:What are the ratings of TRIAC available in market?

A4:Voltage 1200 and Current 300A(rms).

Q5:Give application of Triac?

A5:Give application of Triac?

1. Residential lamp –dimmers.
2. Heat control
3. Speed control of small single phase series and induction motor.

Q6:Is TRIAc have a capability to work in rectifier mode?

A6:Yes

Q7:By what manner Triac is different from SCR?

A7:Bidirectional conduction.

Triac is a combination of two SCRs connected in anti parallel.

Q8:How many layers are there in Triac?

A8:5 layers.

Q9: What is the symbol of Triac?

A9:

Q10: how TRIAC is differ from Diac?

A10:TRIAC have gate terminal and Diac didn’t.