Treedix GM328 Transistor Tester User Manual

The Transistor Tester
user manual

GM328 Transistor Tester

Power：
Transistor Tester can be powered from 6.8V – 12V DC. This can be achieve by a 9V layer-built battery. Two 3.7V Lithium-ion battery in series. Or AC adapter. When power on , the current is about 30mA at DC 9V.

Control:
Transistor Tester is control by a “rotary pulse encoder with switch” , or short by “RPEWS” , this component have four mode of operation, a short time press the knob , press and hold , left and right rotate the knob.
when Transistor Tester is powered. a Short time press of the RPEWS will switch on the Transistor Tester, and start a Test.
Transistor Tester will waiting for user input at the end of a test.
During a end of test ,and before it’s auto switch off. A long time press or Rotation of left and right the RPEWS will enter the function menu. In the function menu, a “>” at left column to index the Selected menu item. To enter the Specific function , just a click the RPEWS. Within the Specific function, press and hold the knob will exit and go back to the function menu.

Test：
Transistor Tester have three Test point(TP1,TP2,TP3), within the Test socket, the three is allocation as follow.

At right side of the Test socket is the SMT test pad, also have number to Identify each.
When test two lead component(resistor, capacitor, inductor), the two lead can select any two test point . if TP1 and TP3 is selected, the Test will enter to” series test mode” when the test is Completes. Else the test is start again by a short time press RPEWS.

Attention: All ways be sure to discharge capacitors before connecting them to the Tester! The Tester may be damaged before you have switched it on. There is only a little protection at the MCU’s ports.
Extra caution is required if you try to test components mounted in a circuit. In either case the equipment should be disconnected from power source and you should be sure, that no residual voltage remains in the equipment.

Self test and Calibration:

the self test can be prepared by connecting all three test point together and pushing of the RPEWS, the color of the Tester’s LCD will change to white font and black background. Prompt string “Self test mode..?”, To begin the self test, the RPEWS must be pressed again within 2 seconds, else the tester will continue with a normal measurement.
Now self test is start, the tester will prompt you for next step. Wait for a time until Prompt string “isolate Probes!”, at that time remove the connecting of the three test point. Tester will wait , until it’s sense the disconnect. Then Tester continue the self test process. If this is the first time use self test(the Transistor Tester is assemble by yourself from scratch ), Tester will soon Prompt string “ 1-||-3 > 100nf” , A capacitor with any capacity between 100nF and 20µF connected to pin 1 and pin 3 is required for the last task of calibration, You should connect the capacitor, not before this text is shown. With this capacitor the offset voltage of the analog comparator will be compensated for better measurement of capacity values.

special using hints:
Normally the Tester shows the battery voltage with every start. If the voltage fall below a limit, a warning is shown behind the battery voltage. If you use a rechargeable 9V battery, you should replace the battery as soon as possible or you should recharge. the measured supply voltage will be shown in display row two for 1 second with”VCC=x.xxV”. It cannot repeat often enough, that capacitors should be discharged before measuring. Otherwise the Tester can be damaged before the start button is pressed. If you try to measure components in assembled condition, the equipment should be all ways disconnected from power source. Furthermore you should be sure, that no residual voltage reside in the equipment. Every electronical equipment has capacitors inside!
If you try to measure little resistor values, you should keep the resistance of plug connectors and cables in mind. The quality and condition of plug connectors are important, also the resistance of cables used for measurement. The same is in force for the ESR measurement of capacitors. With poor connection cable a ESR value of 0.02Ω can grow to 0.61Ω.
You should not expect very good accuracy of measurement results, especially the ESR measurement and the results of inductance measurement are not very exact

Components with problems:
You should keep in mind by interpreting the measurement results, that the circuit of the Transistor Tester is designed for small signal semiconductors. In normal measurement condition the measurement current can only reach about 6 mA. Power semiconductors often make trouble by reason of residual current with the identification and the measurement of junction capacity value. The Tester often cannot deliver enough ignition current or holding current for power Thyristors or Triacs. So a Thyristor can be detected as NPN transistor or diode. Also it is possible, that a Thyristor or Triacis detected as unknown.
Another problem is the identification of semiconductors with integrated resistors. So the base -emitter diode of a BU508D transistor cannot be detected by reason of the parallel connected internal 42Ω resistor. Therefore the transistor function cannot be tested also. Problem with detection is also given with power Darlington transistors. We can find often internal base – emitter resistors, which make it difficult to identify the component with the undersized measurement current.

Measurement of PNP and NPN transistors:
For normal measurement the three pins of the transistor will be connect in any order to the measurement inputs of the Transistor Tester. After pushing the RPEWS, the Tester shows in row1 the type (NPN or PNP), a possible integrated protecting diode of the Collector – Emitter path and the sequence of pins. The diode symbol is shown with correct polarity. Row 2 shows the current amplification factor (hfe=…) and the Base – Emitter threshold voltage. You should know, that the Tester can measure the amplification factor with two different circuits, the common Emitter and the common Collector circuit (Emitter follower). Only the higher result is shown on the LCD.
With Germanium transistors often a Collector cutoff current ICEO with current less base or a Collector residual current ICES with base hold to the emitter level is measured.

Measurement of JFET and D-MOS transistors:
Because the structure of JFET type is symmetrical, the Source and Drain of this transistor cannot be differed. Normally one of the parameter of this transistor is the current of the transistor with the Gate at the same level as Source. This current is often higher than the current, which can be reached with the measurement circuit of the Transistor Tester with the 680Ω resistor. For this reason the 680Ω resistor is connected to the Source. Thus the Gate get with the growing of current a negative bias voltage. The Tester reports the Source current of this circuit and additionally the bias voltage of the Gate. So various models can be differed. The D-MOS transistors (depletion type) are measured with the same method. You should know for enhancement MOS transistors (P-E-MOS or N-E-MOS), that the measurement of the gate threshold voltage (Vth) is more difficult with little gate capacity values. You can get a better voltage value, if you connect a capacitor with a value of some nF parallel to the gate/source. The gate threshold voltage will be find out with a drain current of about 3.5mA for a P-E-MOS and about 4mA for a N-E-MOS

Function menu descriptions:

1. Switch off
   Enter this Function the Tester will shut down immediately.

2. Transistor
   Transistor test, it’s also the default Function at switch on.

3. Frequency
   Measurement of frequency, For frequencies below 25kHz the normal measurement is followed by a measurement of period time. This additional measurement is only followed after a normal frequency measurement.

4. f-Generator
   Signal generation, this Function can output square wave .with various of frequency to choice.

5. 10-bit PWM
   The function ”10-bit PWM” (Pulse Width Modulation) generates a fixed frequency(7812.5Hz) with selectable pulse width at the pin TP2. With a short key press (< 0.5 s) the pulse width is increased by 1%, with a longer key press the pulse width is increased by 10%. If 99% is overstepped, 100% is subtracted from the result. The function can be exit with a very long key press (> 1.3 s).

6. C+ESR@TP1:3
   The additional function ”C+ESR@TP1:3” selects a stand-alone capacity measurement with ESR (Equivalent Series Resistance) measurement at the test pins TP1 and TP3. Capacities from 2µF up to 50mF can be measured. Because the measurement voltage is only about 300mV , in most cases the capacitor can be measured ”in circuit” without previous disassembling. The series of measurements can be finished with a long press of RPEWS.

7. Self test
   With the menu function ”Self test” a full self test with calibration is done. With that call all the test functions T1 to T7 and also the calibration with external capacitor is done every time.

8. Voltage
   Voltage measurement, Because a 10:1(180K:20K) voltage divides is connected , the maximum external voltage can be 50V, The measurement can also be exit by Continuous rotation of the RPEWS.

9. Show data
   The function ,”Show Data” shows besides the version number of the software the data of the calibration. These are the zero resistance (R0) of the pin combination 1:3, 2:3 and 1:2 .In addition the resistance of the port outputs to the 5V side (RiHi) and to the 0V side (RiLo) are shown. The zero capacity values (C0) are also shown with all pin combinations (1:3, 2:3,1:2 and 3:1, 3:2 2:1). At last the correction values for the comparator (REF C) and for the reference voltage (REF R) are also shown. Every page is shown for 15 seconds, but you can select the next page by a key press or a right turn of the rotary encoder. With a left turn of the rotary encoder you can repeat the output of the last page or return to the previous page.

10. Front Color
    This function can change the color of the font, the 16bit color is encode in RGB(565) format, that mean red maximum = 31, green maximum = 63,blue maximum = 31 respectively. In the function, a short time press can index the base color to change, turn left decrease it value and turn right increase it value. A long time press will save the Result and exit the function, please keep in mind the Front Color and the back color cannot be the same. This will case the LCD show nothing. If this happens, you need to do a Self test , how to enter the Self test is descriptions at Page 2. Self test will change the back Color to black and font color to white automatically. When the Self test is finish . you will have the chance to modify the color .

11. Back Color
    This is function is the same as the Front Color except it’s change the background color .

12. 1-||-3
    This function can series Measurement the capacitance at TP1 ,TP3, this function can Measurement very small capacitor. A long time press will exit the function.

13. 1-
    This function can series Measurement the Resistance and inductance at TP1 ,TP3, A long time press will exit the function.

14. DS18B20
    The DS18B20 is a Digital Thermometer with 1 Wire communicating protocol , it Looks like a Transistor due to the component package of TO-92, so it can fit into the Transistor tester. When enter to this function, the Row 2 of the LCD is show a string “1=GND 2=DQ 3=VDD” , it’s mean TP1 of the tester connect the GND of the DS18B20 , and so on. The Tester can not sense the pin distribution of the DS18B20, because DS18B20 is a integrated circuit. Must according to the string to install the DS18B20.
    The Tester read the temperature use 12bit resolution, it first start a “Convert T“[44h] command, and then series read the 9 byte of the “SCRATCHPAD” and the “64-BIT LASERED ROM”. Fetch the first two byte within the “SCRATCHPAD”, conversion this first two byte to readable temperature show at row 3 of the LCD . Scratchpad| BYTE
    ---|---
    TEMPERATURE LSB| 0
    TEMPERATURE MSB| 1
    TH/USER BYTE 1| 2
    TL/USER BYTE 2| 3
    CONFIG| 4
    RESERVED| 5
    RESERVED| 6
    RESERVED| 7
    CRC| 8

For example:
Follow is a read of the DS18B20.
Scratchpad：
EC014B467FFF0C102A
It’s mean

The 64-BIT ROM
For example:
64-bit ROM:
28FF4D58361604A1
meaning

The temperature at row 3 of the LCD is show in decimal system, for the others number is hexadecimal.
Measures temperatures from -55°C to +125°C.
Exit this function can achieve by press and hold the RPEWS > 3s.

15. DHT11
    DHT11 is a sensor with temperature measure and humidity measure, the degree of accuracy is +-5%RH and +-2℃，Measures temperatures from 0 to 50℃ , Measures humidity from 20-90%RH.
    When enter to this function, the Row 2 of the LCD is show a string “1=GND 2=DQ 3=VDD” , it’s mean TP1 of the tester connect the GND of the DHT11 , the “N/A” pin of the DHT11 can be floating, or connect to GND. The TP2 of the tester is connect to DATA of the DHT11, The TP3 of the tester is connect to VCC of the DHT11. The Tester can not sense the pin distribution of the EHT11 , Must according to Above statement.
    When a correctly read is occur, the temperature is show at row 3 and humidity is show at row 4.
    Exit this function can achieve by press and hold the RPEWS > 3s.

16. IR_decoder
    The function of decoder is achieve by a IR receiver module. the follow IR receiver module is choice at design.

17. 1= DOUT 2=GND 3=VCC
    When enter to this function, the Row 2 of the LCD is show a string“1=DOUT 2=GND 3=VCC” , it’s mean TP1 of the tester connect the GND of the IR receiver module, and so on.
    Look like this The function support two infrared remote control protocol
    1. uPD61212. TC9012This two protocol are all same except the lead code, the protocol 1 is 9ms+4.5ms ,but the protocol 2 is 4.5ms+4.5ms A success decode is list at row4 – 8 of the LCD, where row 4 display the IR protocol (TC9012 or uPD6121), row5 and row6 display “User code 1” and “User code 2” , row 7 display the data and the Bitwise NOT of the data(~data). Row8 is display the four byte together. the hexadecimal system is used to display All of the numbers.

18. IR_Encoder
    This function is a simulation of IR Remote Controller. it can drive a IR LED connect at the tester’s PWM output interface associate with the user input . since the tester only provide about 6mA current, the Control distance is less-than a regular IR Remote Controller.
    On the first column of the LCD , is show a “>” , this symbol can move up or down by a click of the rotary encoder to select a certain item.
    Row2 of the LCD is select protocol, like IR_Decoder above, there are two protocol for select, ”TC9012” and “uPD6121”. It can be changed by rotate the knob, when the “>” appear at row2. row3 and row4 change the “user code 1” and “user code 2” value by rotate the knob ,left rotate will decrease and right rotate will increase the value . press and hold the knob for >1S and <3S (>3S will exit this function) will add the value by 0x10 to fast reach to the expect value.
    Row5 change the “data” ,and the Bitwise NOT of the “data” (~data) is auto calculate by the tester .
    Row6 ,The “emit:” is used to start a transmit . move “>” to this line, and rotate the knob ,a “->” will appear soon untill a transmit complete.
    This function is “strongly” correlation with the 16.IR_decoder . without decoder ,the value of the user code and data is unknown. Unless you already know them before. Used other methods.
    The infrared remote control protocol of “TC9012” is frequent use on television in my submission. I think , in china.

19. C(uF)- correction
    This function set the correction value for big capacitor measurement, Positive values will reduce measurement results.

At last:
For more information about the Transistor tester, please visit
http://www.mikrocontroller.net/articles/AVR-Transistortester

The Transistor Tester assembly instructions

This article is a guide to help . when you have received the Transistor Tester Component package. and want to assembly them all together.
First show component list. I recommend that you have to use follow list to Compare before you pick up your soldering iron.

designator| Component  Name| Component  parameters| Footprint| Number of Component
---|---|---|---|---
R19 ,R20| Metal film resistor| 1KΩ    1/4W  1%| Axial0.3| 2
R16| Metal film resistor| 2.2KΩ  1/4W  1%| Axial0.3| 1
R12 ,R7| Metal film resistor| 3.3KΩ  1/4W  1%| Axial0.3| 1
R22,R17,R18,R11,R21,R13| Metal film resistor| 10KΩ   1/4W  1%| Axial0.3| 6
R24| Metal film resistor| 20KΩ   1/4W  1%| Axial0.3| 1
R15,R8| Metal film resistor| 27KΩ   1/4W  1%| Axial0.3| 2
R10| Metal film resistor| 33KΩ   1/4W  1%| Axial0.3| 1
R9| Metal film resistor| 100KΩ  1/4W  1%| Axial0.3| 1
R23| Metal film resistor| 180KΩ  1/4W  1%| Axial0.3| 1
R14| Metal film resistor| 220Ω   1/4W  1%| Axial0.3| 1
R4,R2,R6| Metal film resistor| 470KΩ  1/4W  1%| Axial0.3| 3
R1,R3,R5| Metal film resistor| 680Ω   1/4W  1%| Axial0.3| 3
Y1| Quartz crystal| 8Mhz| HC-49| 1
C7 ,C8| ceramic capacitor| 22pF 20%    silk( 220)| RAD0.2| 2
C1| ceramic capacitor| 1000pF 20%   silk( 102)| RAD0.2| 1
C2| ceramic capacitor| 10nF  20%   silk( 103)| RAD0.2| 1
C3,C4,C5,C6,C11| ceramic capacitor| 100nF 20%   silk( 104)| RAD0.2| 5
CESD| ceramic capacitor| 100nF 20%   no silk| 805| 1
C9,C10| Aluminum electrolytic capacitor| 10uF  20%| RB.2/.4| 2
T3| bipolar junction transistor| PNP   silk(9012)| TO-92| 1
T1 、T2| bipolar junction transistor| NPN   silk(9014)| TO-92| 2
U1| AVR MCU| ATMEGA328P-PU| DIP28| 1
U2| Regulator| HT7550| TO-92| 1
U3| Precision References| TL431| TO-92| 1
ESD| Low Capacitance TVS Diode Array| SRV05-4   silk(MC5)| SOT-23 6L| 1
ZD| Transient Voltage Suppressors（TVS）| P6KE6V8  silk(6V8C)| 1812| 1
LED1| Light Emitting Diode| Φ3MM| | 1
J3| Test bench| 14P| DIP14| 1
DC1| DC jack| 5.5-2.1MM| DC-005| 1
TEST1| rotary pulse encoder with switch| | | 1
J4,J5,JP1| connecting terminal| Lead space 5.08MM| | 3
J2| pin header and Female Header| 8P| | 1 each
| copper pillar| 3MM 11MM| | 6
| bolt| 3MM| | 8
| TFT LCD module| 160120 pixel with 16bit full color| | 1
| Main board PCB| 60 * 77 MM| | 1

The Transistor Tester have three SMT Components: Their designator are ZD,CESD and ESD. The three Components should besoldering first, because they are the smallest size in the whole Components.

Their role is to protect the MCU against Transient high voltage. In fact . the Transistor Tester can normally work without they three part . The ZD and CESD have no polarity, so you can soldering this two with no matter. The ESD have six pins . need first to  find she’s PIN 1,follow photo will help you

(note: on the top, the silk maybe “MC5” or “VC5” or “LC5”, they mean same)
In the Transistor Tester main board PCB,

the ESD is the most difficult part to soldering. if not sure, you can leave this empty . it’s not a mistake.
When you have done the three , use some organic solvent like (absolute ethyl alcohol or Thinner or other Plate washer water ) to clean before next.
Next:
The Metal film resistor can now soldering, on the Transistor Tester main board PCB, all of the resistor’s installation site is printed with the expect value. So you can easy to find out the right one for each , if don’t sure about the Color ring, meter once before soldering . this photo can help you recognition .

Next, the ceramic capacitor can be soldering, ceramic capacitor do not have polarity . The Transistor Tester main board PCB is printed the capacitor’s value for each. And the ceramic capacitor body also silk it value ,so this is clear enough for you . the exception is the 22pF , the PCB is printed “22”, but the ceramic capacitor is silk 220, they are same thing.
The Aluminum electrolytic capacitor have polarity, the positive have the longer lead than it negative. it installation site is printed it value, and the positive is carry with a “+”. On the shell of the Aluminum electrolytic capacitor, a wide band with white color is point it negative side .

The light-emitting diode have polarity, like the Aluminum electrolytic capacitor, the positive have the longer lead than it negative.
On the PCB

The Quartz crystal have no polarity.
When you soldering the Test bench, please keep hand shank in unlock state.

For the rest of the Component package , is simple enough. I will attached some photo at the last of the article.
Very important note:
When you have complete the soldering, maybe you will use some “Plate washer water” to clean the soldering side, when doing so . please keep Care about the “rotary pulse encoder with switch”, this Component’s body cannot contact any “Plate washer water” except it Pins. The “Plate washer water” can destroy the internal of the “rotary pulse encoder with switch”.
The same rule is apply the “TFT LCD module” too, the “TFT LCD module” cannot meet “Plate washer water” anywhere.

The three SMT part. transistor tester can regular work without them , with no problem, yes. When finish, clean them for next step.

The metal film resistor , there have some confusing is the 33K and 3.3K , 2.2K and 220, mind you.
This two look much the same.

References

• baidu.com/link?url=K1wRveLeJL5fllkfDkTx3pMjU-9KfmPYb6OnICUZCqcNdbvjm6PeuMmWcJyT3fPxKvHpfEkcCdnvGrCBsu7Cxst8PNkCUaGF3cNJunPDGOm5VgDAGJlEJ_zNh765VZml&wd=&eqid=d918a5f60000c4ca0000000557ca60c6
• baidu.com/link?url=sjlDDwzsVlqlzXmclHA35HGkVvxLcz3LTSm_S6gLJtd7HHr91NJvTUYZOZwdSEHLsS7N2rnYhq45RBdNrV7ljapaWtzie_P6GH5S7swtFPncFA31RnQbPWTooUZ7OaOd&wd=&eqid=b983bbf60040d971000000055708f6e9
• 瞬态电压抑制二极管Transient Voltage Suppressors（TVS） - LabVIEW开发者 - 博客园
• AVR-Transistortester – Mikrocontroller.net

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