PE02 MOSFET Characteristics Operating Manual Ver.1cgibp.com/data/lab_manual/PE02 MOSFET...

PE02 MOSFET Characteristics

Operating Manual Ver.1.1

An ISO 9001 : 2000 company

94-101, Electronic Complex Pardesipura, Indore- 452010, India Tel : 91-731- 2570301/02, 4211100 Fax: 91- 731- 2555643 e mail : [email protected] Website : www.scientech.bz Toll free : 1800-103-5050

mailto:[email protected]

http://www.scientech.bz

PE02

Scientech Technologies Pvt. Ltd. 2

PE02


RoHS Compliance

Scientech Products are RoHS Complied. RoHS Directive concerns with the restrictive use of Hazardous substances (Pb, Cd, Cr, Hg, Br compounds) in electric and electronic equipments. Scientech products are “Lead Free” and “Environment Friendly”. It is mandatory that service engineers use lead free solder wire and use the soldering irons upto (25 W) that reach a temperature of 450°C at the tip as the melting temperature of the unleaded solder is higher than the leaded solder.

PE02 MOSFET Characteristics

Table of Contents

1. Introduction 4

2. Theory 6

3. Experiments Experiment 9 To study the characteristics of n channel MOSFET

4. Data Sheet 12 5. Warranty 14

6. List of Accessories 14

PE02


Introduction PE02 is a compact, ready to use MOSFET Characteristics experiment board. This is useful for students to plot characteristics of n channel MOSFET and to understand various region of operation of it. It can be used as stand alone unit with external DC power supply

List of Boards : Model Name PE01 UJT Characteristics PE03 SCR Characteristics PE04 TRIAC Characteristics

PE05 DIAC Characteristics PE06 IGBT Characteristics` PE07 PUT Characteristics PE10 SCR Triggering (R, RC Full wave, RC Half wave)

PE11 SCR Triggering (UJT) PE12 SCR Triggering (IC555) PE13 SCR Triggering (IC74121) PE14 Ramp and Pedestal triggering

PE15 SCR Triggering (IC741) PE16 SCR Triggering (PUT) PE40 SCR Lamp Flasher PE41 SCR Alarm Circuit PE42 Series Inverter PE43 UJT Relaxation oscillator

PE44 Signal Phase PWM Inverter

PE02


List of other Boards available are : Model Name ST2701 IGBT Characteristics ST2702 SCR Triggering (R, RC Half wave, RC Full wave) ST2703 SCR Triggering Techniques

ST2704 Triggering of SCR using 74121 IC ST2705 SCR Lamp Flasher ST2706 SCR Alarm Circuit ST2707 Series Inverter ST2708 Single Phase Controlled Rectifier

(With Ramp Comparator Firing Scheme) ST2709 Single Phase Controlled Rectifier with Cosine

Firing Scheme ST2710 Single Phase Converter Firing Techniques

ST2711 Lamp Dimmer ST2712 Power Electronics Lab

ST2713 Single Phase Cycloconverter

ST2714 Speed Control of Universal Motor Using SCR

ST2715 Speed Control of AC Motor Using TRIAC

ST2716 Micro Controller Based Firing Circuit for Controlled Rectifier

ST2717 SCR Commutation Circuits

ST2718 Bedford and Parallel Inverter

and many more…

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Theory FET with an oxide coating between gate and channel is called a MOSFET (metal- oxide semiconductor field effect transistor) the figure below shows the oxide, insulating the gate from the channel. MOSFET is voltage controlled device & required only small input current. Its switching speed is very high; it is used in low power high frequency converter. But it has the problem of electrostatic discharge so require special care in handling. As a result, the MOSFET has very high input resistance, higher than the JFET; and as with the JFET, the gate controls the main or channel current, Ids.

Figure 1

Notice that a positive gate voltage will induce a negative charge in the n channel, enhancing the drain-source current, Ids; while a negative gate voltage will induce a depletion region in the n- channel, thereby reducing the drain-source current, Ids. A MOSFET so constructed is a depletion/enhancement MOSFET. A typical n-channel MOSFET curve is shown below.

Figure 2

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Figure1 shows the transconductance, Gm, or effect of the gate voltage upon the drain to source current. Notice the gate-source voltage can be positive or negative. This would not be possible with a JFET. In figure 2 again notice the effect of increasing Vgs on Ids; notice also that for any given gate current, the drain-source voltage has little effect upon the drain current above 3 volts, since the MOSFET is in saturation.

The MOSFET is also made in an enhancement-only mode, where a gate signal only induces or enhances channel current, the gate signal never depletes the channel current. Naturally there are p-channel enhancement MOSFETS, where a negative gate voltage enhances channel conductivity; and n-channel enhancement mode MOSFETS where a positive gate voltage enhances channel conductivity. One final note, breakdown voltage in MOS devices do not depend upon p-n junction stress but rather upon the thickness and quality of the insulating oxide. When breakdown does occur, the oxide is punctured and the device is destroyed.

Figure 3

Here drain current is cut-off until the gate to source voltage reaches a specific magnitude. So, current control in n-channel is effected by +ve source to gate voltage.

If VGS is set to zero, voltage applied between D & S of the device, the absence of n-channel will result in current zero amperes. With VDS some +ve voltage, VGS at zero volts & terminal ss is directly connected to source there are in fact two reverse biased p-n junction between the n-doped & p-substrate to oppose any significant flow between drain & source.

Now of VGS & VDS is set at some +ve voltage greater then zero, hence established D-gate at +ve potential with respect to source.

As VGS is increase, then significant increase in drain current (ID) is called threshold voltage & given by VT.

PE02


Since channel is non-existence with VGS= 0V and enhanced by the application of +ve gate-to-source voltage so this type of MOSFET is called enhancement type.

So with increase in VGS, drain current increase. If we hold VGS constant & increase in level of VDS then ID will eventually reach saturation level

For value of VGS less than the threshold level the drain current of an enhancement type MOSFET is 0 mA.

Enhancement type MOSFET characteristics

Figure 4

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Experiment Objective : To study the characteristics of MOSFET Equipments Needed : 1. Power Electronics Board, PE02 2. DC power supplies + 15 V and + 35 V.

3. Digital multi-meter. 4. 2mm patch cords.

Circuit diagram : Circuit used to plot different characteristics of MOSFET is shown in figure 5.

Figure 5

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Procedure : • Connect +35 V and +15 V DC power supplies at their indicated position from

external source. 1. To plot drain characteristics proceed as follows:

2. Rotate both the potentiometer P1 and P2 fully in counter clockwise direction. 3. Connect Ammeter between test point ‘2’ and ‘3’ to measure gate current IG

(mA) between test point ‘4’ and ‘5’ to measure drain current ID(mA). 4. Short or connect a 2mm patch cord between test point ‘4’ and ‘5’.

5. Connect one voltmeter between test point ‘6’ and ground to measure drain voltage VDS other voltmeter between test point ‘1’ and ground to measure gate voltage VGS.

6. Switch ‘On’ the power supply.

7. Vary potentiometer P2 and set a value of gate voltage VGS at some constant value (3 V, 3.1 V, 3.2 V)

8. Vary the potentiometer P1 so as to increase the value of drain voltage VDS from zero to 35 V in step and measure the corresponding values of drain current IE for different constant value gate voltage VGS in an observation table.

9. Rotate potentiometer P1 fully in counter clockwise direction.

10. Repeat the procedure from step 6 for different sets of gate voltage VGS. 11. Plot a curve between drain voltage VGS and drain current 10 using suitable scale

with the help of observation table. This curve is the required drain characteristic.

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Observation Table :

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Data Sheet

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PE02


Warranty 1. We guarantee the product against all manufacturing defects for 24 months from

the date of sale by us or through our dealers. Consumables like dry cell etc. are not covered under warranty.

2. The guarantee will become void, if

a) The product is not operated as per the instruction given in the operating manual.

b) The agreed payment terms and other conditions of sale are not followed.

c) The customer resells the instrument to another party. d) Any attempt is made to service and modify the instrument.

3. The non-working of the product is to be communicated to us immediately giving full details of the complaints and defects noticed specifically mentioning the type, serial number of the product and date of purchase etc.

4. The repair work will be carried out, provided the product is dispatched securely packed and insured. The transportation charges shall be borne by the customer.

For any Technical Problem Please Contact us at [email protected]

List of Accessories

1. 2 mm Patch Cords (Red) ...................................................................... 2 Nos. 2. 2 mm Patch Cord (Black) ..................................................................... 2 Nos. 3. 2 mm Patch Cord (Blue) .........................................................................1 No. 4. e-Manual.................................................................................................1 No.

Updated 21-02-2009

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