The latest version can test the DS18B20 and DHT11 and IR_decoder

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 shorttime
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 “ Selftest 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 0.02ohm can grow to 0.61ohm.
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 42ohm 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 680ohm
resistor. For this reason the 680ohm 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