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Dual Bench Power Supply

and Multifunction Tester

bench power supply

A dual bench power supply for building and testing of electronic projects.

 

 

 

Features/Functions

Dual Programmable Power Supply Modules 1 x 3A & 1 x 5A with 10x preset memories each

Continuity Tester

Logic Probe

Voltmeter

Transistor, Diode, Capacitance, LED and Resistance Tester

IR decoder, IR encoder

DHT11 and DS18B20 Tester

Frequency Generator and Frequency measurement

10-bit PWM

 

 

 

Front Panel Layout

bench power supply animation

 

 

 

 

 

Enclosure

I have used a Bud Industries PC-11491 Plastic Desktop Enclosure made from ABS with a sloped aluminum front panel.

This was purchased from Farnell

The enclosure is 99.95 mm, 220.98 mm, 155.7 mm

bud industries pc-11491

 

Enclosure Drawing (in inches)

 

 

 

 

Construction

The modules and boards are all mounted on the aluminium front panel. The panel is cutout and drilled to take the displays and non power supply inputs.

 

 

The outputs from the twin power supplies are on the back of the enclosure using standard 4mm banana sockets.

There are 2 pairs of outputs for each programmable power supply. The 3A programmable power supply also has a sprung output connector for bare wires.

There is also an input and output for a DCF77 signal supply.

The DC Input feed plugs in a power socket also mounted on the rear of the enclosure.

 

bench power supply

 

 

 

Aluminium Front Panel Dimensions & Cutouts

 

 

 

Panel Cutout Plan

 

Panel Cutout with Switches and Modules

 

 

 

Panel Print layout for printing onto Inkjet Transfer Paper

 

 

 

Blank white painted panel ready for the inkjet transfer

 

 

The transfer is sprayed with clear varnish, allowed to dry then soaked in water.

 

 

The transfer is then slid into place on the front panel.

 

 

Completed front panel with inkjet transfer applied

 

 

 

 

 

 

Schematic

 

 

 

 

 

Continuity Probe

by
MitchElectronics 2019


www.mitchelectronics.co.uk

My continuity probe is made from a kit available from www.mitchelectronics.co.uk .

Taken from the Continuity probe Manual

 

 

 

A continuity probe has two probe points that are used to determine if there is an electrical connection between two points.

If the two probes probe the same wire then the continuity probe makes a beep sound and if there is resistance between the probe points (or no connection at all), then the continuity probe makes no sound at all.


A simple continuity probe could be built with a buzzer, a battery, and two probes which combine to make a simple buzzer circuit.

While this is fine for checking the continuity of wires (ensure the wire is properly connected and undamaged), it is not recommended for potentially sensitive circuits.

Applying power to a circuit can potentially cause reverse bias or worse a large current rush could damage com-ponents such as LEDs.

Therefore, a proper continuity probe is needed which can check for low re-sistance but not damage sensitive parts!



 

The MitchElectronics continuity probe is made up of two main sub-circuits

Comparator schematic and Gated Oscillator schematic

 


The comparator stage is made up of an op-amp and various components whereby the two voltages that are compared are the voltage present at Probe 2 and across R7.

The voltage across R7 is approximately 0.6V * 1/3 = 0.2V and if the two probes are not connected (i.e. there is no continuity) then the voltage across R5 is 0V which means that the output of op-amp U1A is 0V.

This output is fed into a gated RC os-cillator made using a Schmitt trigger. If the input to the gated oscillator is 0V then the output of the NAND gate stays high and if the input is equal to VCC then U2A can oscillate.

This oscillation is buffered by the NAND gate U2B and this buffered square wave is fed into a buzzer.


When the two probes make electrical contact with each other (through a wire or PCB trace), the volt-age across R5 is equal to 0.6V / 2.

As the potential divider circuit (made up of R2 / R5) is connected to a forward biased diode D1 whose forward voltage is 0.6V.

The 0.3V from this divider is greater than the 0.2V across the resistor R7 which means that the output of U1A goes to VCC when there is continuity between the two probes.

The reason for using diodes to produce a 0.6V reference is to keep the voltag-es from the probes below 0.6V which is low enough to prevent damage to sensitive parts such as ICs.


MitchElectronics

 

 

Kit Components

 

I did not use the 9v battery connector that came with this kit but connected it to a 9v regulated power supply.

 

 

 

 

 

 

Logic Probe Kit


MitchElectronics 2018

www.mitchelectronics.co.uk

My logic probe is made from a kit available from www.mitchelectronics.co.uk .

Taken from the Logic probe Manual

 Instead of having numbers to show voltages or a dis-play to show signals over time the logic probe has just three LEDs for outputs.

These outputs can show the following conditions:

Red LED Off

Yellow LED Floating

Green LED On

All LEDs Oscillating

 

SCHEMATIC EXPLANATION


So long as the probe has a common ground to the circuit under test (which can be done easily by either using the same power supply or connecting the probes GND-REF to the circuits ground),

the probe will display one of the four listed conditions above when the probe contact is connected to a point in the circuit.


The logic probe uses a 4001 quad NOR gate IC, resistors and a capacitor. The first NOR gate is used as abasic oscillator.

With the inputs connected together the first NOR gate is transformed into an inverter.


R3 is used to feed the output back into the input which results in oscillation if the input is unconnected (floating).


D2 is connected between power through R1 and the output of the NOR gate while D3 is connected toground through R5 and the output of the NOR gate.

If the input to the NOR gate is a logical 1 then the NOR gate will output 0V and this will result in D2 turning on (current flows through R1, through D2 and then into the output which is at 0V).

If the input is off then the output of the NOR gate will be VDD and this results in D3 turning on instead of D2 (current flows from the output of the NOR gate through D3 and then to ground through R5).


The next two NOR gates form a basic mono-stable circuit which is used to detect an oscillating signal.

If for example the input signal was oscillating at a high rate (more than a MHz), then any LED that is used to show this signal would not be very bright and thus make it hard to tell if the input is oscillating.

To solve this the mono-stable formed by the second two NOR gates, capacitor (C1) and resistor (R2) will be constantly triggered and re-triggered by the oscillating input.

This results in a constant output which will make an LED bright so long as the oscillation is present. The last NOR gate is used as an LED driver for the mono-stable.


If no input is connected (floating), the NOR gate will weakly oscillate around VCC / 2. The voltage seen by both D2 and D3 will be approximately half VCC and thus results in neither LED turning on and therefore indicates a floating input.

This weak oscillation, however, is able to set and reset the monostable which keeps the yellow LED on.


NOTE ON USING THE LOGIC PROBE

The logic probe will only work properly if the GND-REF pad is connected to the ground of the circuit under test.

If the ground in the logic probe is not the same as that of the test circuit then there is no return path for any signals which results in the logic probe not being able to take measurements.


In other words, signals can only be measured with respect to some level.

There is not such this as an absolute voltage, voltage is relative because it is always with respect to some user defined point.

An common example is the mains wiring: The neutral wire is 230VAC with respect to the live wire but 0VAC with respect to earth (and hence you).

Kit Components

I did not use the 9v battery connector that came with this kit but connected it to a 9v regulated power supply.

 


 

 

Constant Voltage / Constant Current

Programmable Power Supply

DC32V3A DPS3003

Model:DPS3003

General Information

 

Description: Constant voltage and constant current programmable power supply module.

 

Programmable Step Down Power Supply Module



Features: Fast operation for voltage and current settings.

Adjustable output voltage range from 0V-32V/50.00V(optional), adjustable output current range from 0-3.000A/5.000A(optional). Set default boot open or close the output.

The module can store 10 groups of preset values and it can quickly extract 2 groups of preset values.

LCD display and voltage/current meter function, you can view the preset voltage/current, input voltage, output voltage/current, output power, etc.

In the output state display area, it is convenient for you to know whether the output works, constant voltage/current output state, current data group extracted, etc.

Specifications:

Model Type: DPS3003

Input Voltage: DC6-40V

Output Voltage: 0-32.00V

Output Current: 0-3.000A

Output Power: 0-96W

Voltage Resolution: 0.01V

Current Resolution: 0.001A

IN+: Input Positive

IN-: Input Negative

OUT+: Output Positive

OUT-: Output Negative

Item Size: 8*4.2*4.5cm / 3.1*1.7*1.8in

Item Weight: 65-88g / 2.32-3.1oz

Package Size: 8*5*5cm / 3.1*2*2in

Package Weight: 90-113g / 3.2-4oz

Technical parameters

Input Voltage range:  3.00-32.00V                           Output Voltage range:  0-30.00V

Output Current: 0-3.00A                                           Output Power range: 0-1000W   

Product Weight: 222g                                          Display module size: 79*43*38(mm) (L*W*H)

Display module enclosure cutout size:  71mm*39mm  

Power module size: 93*71*41(mm) (L*W*H)  

Mounting holes center distance: 86mm, 64mm   Display connection cables - length: 200mm       

Output Voltage resolution: 0.01V (10mV)        Output Current resolution: 0.01A (10mA)

Output Voltage accuracy: ± (0.5% + 1 digit)       Output Current accuracy: ± (0.5% + 2 digits)

 

NOTES: 

1.       You must ensure that the input Voltage is at least 1.1 times higher than the output Voltage. 

2.       When the unit is mounted in an enclosure it is absolutely vital to ensure appropriate ventilation for heat dissipation. 

3.       Pay careful attention to the correct orientation and placement of the cables between the display / control module and the Power control module. Failure to do so will cause incorrect operation of the unit.

Note: The input Voltage range is DC 6.00-32.00V. 32.00V DC is the maximum input Voltage limit.

 Always ensure an adequate safety margin and ensure that your OFF LOAD input supply Voltage does not exceed the maximum allowed. Failure to do so can result in considerable damage to the unit.  

Even though this module is designed with reverse polarity input protection and output short circuit protection you must still ensure that connections to the unit are in accordance with the connection details.

If the Input Power Supply is connected to the output terminals then the unit will be severely damaged.  

The input must be DC Power only. AC or AC Mains supply 110 or 220V must NEVER under any circumstances be connected to this unit.

Apart from the immediate and potentially fatal risk of electrocution this will cause major, irreparable damage to the unit. 

 

Panel description

1.  Voltage setting / Up Arrow / Shortcut to recall M1 Data Group.

2.  Data entry / Extract data from the specified Data Group / Store value into the specified Data Group.  

3.  Current Limit setting / Down Arrow / Shortcut to recall M2 Data Group.

4.  1.44 inch full colour LCD screen.  

5.  Rotary control / Data adjustment / Key lock.

6.  Output On / Off.  

 

Display interface description

7.     The preset value of the output Voltage.

8.     The actual value of the output Voltage.  

9.     The actual value of the output Current.  

10.  The actual value of the output Power.  

11.  The actual value of the input Voltage.  

12.  The preset value of the output Current Limit.  

13.  Keypad locked or unlocked prompt.  

14.  Normal or abnormal status prompt.

15.  Constant Voltage or Constant Current status prompt.   

16.  Data Group number in use prompt.

17.  Output enabled or disabled prompt  

The Main Interface

 

 

 

18.  Preset output Voltage.  

19.  Preset output Current Limit.  

20.  Preset Over-Voltage Limit.

21.  Preset Over-Current Limit.  

22.  Preset Over-Power Limit.

23.  Preset screen brightness level.

24.  Preset Data Group number.  

25.  The actual value of the output Voltage and output Current.  

Data Setting Interface

Rotary Control Knob

The control knob is a rotary encoder with a push switch.

The control can be pushed in (non locking) and rotated left or right.

 

Operating instructions

When the unit is first powered on the Welcome screen is displayed followed shortly by the Main Interface screen.

 

 

 

 

On the Main Interface screen the selected (SET) Voltage and Current Limit values are displayed on the top of the screen.

When the output is enabled the actual real output Voltage, Current and Power are displayed in the large font.

The actual input Voltage is displayed at the bottom of the screen. On the right side of the screen are icons and prompts indicating system status.

These are: keypad lock state icon, abnormal output status icon, Constant Voltage / Constant Current icon, preset Data Group memory number (when selected) and output enabled / disabled icon.

 

Set the output Voltage and output Current Limit via the Main Interface.

Press V/key to enter the Voltage setting mode.

The Voltage setting numeric value will be highlighted by the cursor.

Press the rotary control to place the cursor at the required character of the numerical value you wish to change.

 Further presses of the rotary control will cycle through the characters available.

Turning the rotary control clockwise increases the value and anticlockwise decreases the value.

Press V/again to exit. Alternatively, after 30 seconds of inactivity the setting mode will exit automatically. 

Press A/to set the output Current Limit using the same procedure.

 

Set data values via the Data Setting Interface

 

Entering the Data Setting Interface

On the main interface press the SET key to enter the Data Setting Interface.

 

Set Voltage and Current Limit values

In the Data Setting Interface press V/or A/to step up or down through the menu options to select U-SET (Voltage) or I-SET

(Current Limit), and then set the output Voltage and output Current Limit in the same way as used in the main interface.

Press the SET key to return to the menu options and press the SET key again to exit.

 

 

 

 

 

 

Set the Protection Values. 

Press V/or A/to step up or down through the menu options to select S-OVP (Over-Voltage Protection),

 

S-OCP (Over-Current Protection)

 

 

or S-OPP (Over-Power Protection) limits.

 

 

 Press the rotary control to place the cursor at the required character of the numerical value you wish to change.

Set the value required in the same way as used in the main interface. Press the SET key to return to the menu options and press the SET key again to exit.

When any of the protection value limits are reached the output will be automatically disabled.

These are the global system protection limits and should not be confused with preset Voltage and Current.

 

Adjust the Screen Brightness  

Press V/or A/to step up or down through the menu options to select B-LED, and then press the rotary control to highlight the brightness setting value.

Turn the rotary control to adjust the brightness from 0 to 5 where 0 is the darkest and 5 is the brightest.

Press the SET key to return to the menu options and press the SET key again to exit.

 

Data settings for each Data Group

 Selecting the Data Group to edit  

Press V/or A/to step up or down through the menu options to select M-PRE, and then press the rotary control.

Turn the rotary control to select the number of the Data Group you wish to view and edit.

After completing the desired setting press and hold the SET key until the Data Group number is shown on the right hand side of the screen.

Pressing the set key again returns to the Data Group menu options.

 

Selecting M-Pre ON / OFF

Press V/or A/to step up or down through the menu options to select M-PRE, and then press the rotary control.

Turn the rotary control to select the number of the Data Group you wish to view and edit then press the rotary control again to allow modification of the M-PRE option.

Turn the rotary control to select either ON or OFF. When ON is selected it signifies that when the Data Group is recalled the state of the unit main output will remain the same as it was prior to the Data Group recall.

When OFF is selected it signifies that when the Data Group is recalled the state of the unit main output will be set to OFF regardless of previous setting.

Press and hold the SET key until the Data Group number is shown on the right hand side of the screen. The data value is now saved to the indicated Data Group number.

Pressing the set key again returns to the Data Group menu options. To exit the Data Group menu press the set key again.

 

Adjust the selected DATA Group numerical values

To adjust any of the numerical values for the selected Data Group first use the V/or A/to step up or down through the menu options to select the item to change.

Then press the rotary control and the numeric value will be highlighted by the cursor. Further presses of the rotary control will cycle through the characters available.

Turning the rotary control clockwise increases the value and anticlockwise decreases the value. After setting the desired value press and hold the SET key until the Data Group number is shown on the right hand side of the screen.

The data value is now saved to the indicated Data Group number. Pressing the set key again returns to the Data Group menu options.

Repeat the above process for changing any of the other numerical values for the selected Data Group. To exit the Data Group menu press the set key again.

 

Selected Data Group output state at power on

Press V/or A/to step up or down through the menu options to select S-INI and then press the rotary control to allow modification of the S-INI option.

Turn the rotary control to select either ON or OFF. Selecting ON means the device will Power on with the Output enabled. Selecting OFF means the device will Power on with the Output disabled.

After selecting the desired setting press and hold the SET key until the Data Group number is shown on the right hand side of the screen.

The data value is now saved. Pressing the set key again returns to the Data Group menu options.

To exit the Data Group menu press the set key again.  

 

Other functions

Enable or Disable the Output.  

At any time you can press the ON/OFF key to enable or disable the Output.

 

Locking the keypad to avoid accidental operation.

The keypad operation can be disabled to avoid accidental operation and unwanted changes.

At any time you can simply press and hold the rotary control for more than 3 seconds to either lock or unlock all keys.

The status of the key lock will be displayed at all times via the lock icon on the right side of the screen. Keypad locked is indicated by a closed padlock.

Keypad unlocked is indicated by an open padlock.  

 

M0-M9 Data Groups

M0 Data Group

The M0 Data Group is a special case. It is the power default Data Group.

It should be noted that any time an alternative Data Group is selected or any changes made to the existing settings then M0 will be immediately overwritten with the newly selected data.

In effect, M0 is always a real-time duplicate of the currently selected Data Group and data values. It is also the data-set that will be saved at power off and recalled at next power on.

This happens automatically and transparently with no input necessary from the user.

 

Shortcut keys to select and recall M1 or M2 Data Group

From the main interface, press and hold V/or A/for more than 3 seconds to quickly recall the M1 or M2 Data Group.

The corresponding Data Group number will displayed on the right of the screen.

The M1 and M2 Data Groups are ideal choices for commonly used settings due to the quick recall function.

   

Select and recall any specific Data Group.

From the main interface, press and hold the SET key more than 3 seconds, M0 will be displayed on the right side of the screen.

Turning the rotary control allows selection of the required Data Group (M1 to M9). To activate the selected Data Group press the SET key.  

 

 

 

 

 

 

Multifunction Tester

The tester often sold as a "Component Tester Transistor Signal Generator Tools Diode Capacitance ESR Meter" can be purchased prebuilt as below or as a kit of parts.

 

I purchased the kit of parts so I could choose a custom fit into my case.

 

 

 

PCB Connections

 

Multifunction Tester Panel Controls

Power :

The Transistor Tester can be powered from 6.8V – 12V DC. This can be achieved by a 9V layer-built battery, two 3.7V

Lithium-ion battery in series or an AC adapter. When powered on the current is about 30mA at DC 9V.

I use an adjustable voltage module fed from the input to feed this circuit, the logic probe and continuity tester.

 

Control:

Transistor Tester is controlled by a “rotary pulse encoder with switch” , or shortened by “RPEWS” , this component has four modes of operation, a short press, press and hold and left and right rotation.

 

When the Transistor Tester is powered a Short press of the RPEWS will switch on the Transistor Tester, and start a Test.

 

The Transistor Tester will wait for user input at the end of a test.

 

During the end of test and before auto switch off  a long press or rotation left or 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 function press and hold the knob will exit and go back to the function menu.

 

Test :

The Transistor Tester has three Test point(TP1,TP2,TP3), within the Test socket, the three are allocated as follows.

 

When testing a two lead component (resistor, capacitor, inductor), use TP1 and TP3 the Tester will enter series test mode.  When the test is complete the test is repeated by a short press of RPEWS.

 

Warning:

To prevent damage to the tester all ways make sure to discharge capacitors before connecting them to the Tester!

 

Extra caution is required if you try to test components in a circuit. In either case the equipment should be disconnected from the power source and you should be sure, that no residual voltage remains in the equipment.

 

 

Self-test and Calibration:

Connect all three test points together and push of the RPEWS, the colour of the

Tester’s LCD will change to a white font and black background. With a Prompt “Self-test mode..?”. To begin the self-test the RPEWS must be pressed again within 2 seconds or the tester will continue with a normal measurement.

 

Once the self-test has started, the tester will prompt you for the next step. Wait for a time until Prompt  “ isolate Probes! ”.

 

Remove the wires connecting the three test points. Tester will wait until it’s senses the wires are removed. Then continue with the self-test process. If this is the first time the self-test has been used (the Transistor Tester is assemble by yourself from scratch ), Tester will soon Prompt “ 1-||-3 > 100nf”. A capacitor with any capacity between 100nF and 20µF should be connected to pin1 and pin 3. Only connect the capacitor once the prompt is displayed. With this capacitor the offset voltage of the analogue comparator will be compensated for better measurement of capacity values.

 

 

Battery Warning:

Normally the Tester shows the battery voltage on start-up. If the voltage falls below a limit, a warning is shown behind

the battery voltage. If you use a rechargeable 9V battery or standard 9v battery replace/re-charge as appropriate.

The measured supply voltage will be shown in display row two for 1 second with”VCC=x.xxV”.

 

Usage Hints:

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 circuit the equipment should be all ways be disconnected from the power source.

Furthermore, you should be sure that no residual voltage resides in the equipment. Most electronic equipment has capacitors inside!

 

If you try to measure a small resistor value, 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 goes for the ESR measurement of capacitors. With a 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 cause problems due to residual current with the identification and the measurement of junction capacity value. The Tester often cannot deliver enough driving current or holding current for power Thyristors or Triacs. So a Thyristor can be detected as NPN transistor or diode. It is also possible that a Thyristor or Triac is detected as unknown.

 

Another problem is the identification of semiconductors with integrated resistors. 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.

Power Darlington transistors also cause problems with detection. We often find internal base - emitter resistors which make it difficult to identify the component with the small measurement current available.

 

Measurement of PNP and NPN transistors:

For normal measurement the three pins of the transistor can be connected 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. 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 cut off 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 parameters 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.

 

The D-MOS transistors (depletion type) are measured with the same method.

 

MOS transistors (P-E-MOS or N-E-MOS) 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 measured 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 he 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 only output a square wave with various frequencies to select.

 

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 you select over 99% the pulse width goes back to 1%. The function can be ended 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” . The series of measurements can be finished with a long press of RPEWS.

 

7.Self-test

With the menu function ”Selftest” a full self-test with calibration is done. With this option all the test functions T1 to T7

including the calibration with external capacitor is done every time.

 

8. Voltage

Voltage measurement, Because a 10:1(180K:20K) voltage divider is connected the maximum external voltage can be

50V.  The measurement can also be ended 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). The last 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. FrontColor

This function can change the colour of the font, the 16bit colour is encoded in RGB(565) format, this means red maximum = 31, green maximum = 63,blue maximum = 31 respectively. In the function, a short press can index the base colour to change, turn left decrease it value and turn right increase it value. A long press will save the Result and exit the function. Please bear in mind the FrontColor and the backcolor cannot be the same (the LCD show nothing).

 

If this happens, you need to do a Self test , how to enter the Self test is described in Page 2. Self test will change the back Color to black and font color to white automatically. When the Self test is finished you will have the chance to modify the colour.

 

11. BackColor

This is function is the same as the FrontColor except it’s changes the background colour.

 

12. 1-||-3

This function series Measures the capacitance at TP1 ,TP3, this function can Measure very small capacitors. A

long press will exit the function.

 

13. 1- - 3

This function series Measures the Resistance and inductance at TP1 ,TP3, A long 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 entering this function, the Row 2 of the LCD is show a string “1=GND 2=DQ 3=VDD” it’s means TP1 of the tester connect the GND of the DS18B20 and so on.

The Tester cannot sense the pin distribution of the DS18B20, because DS18B20 is an integrated circuit. Make sure you connect the pins according to the on-screen prompt.

The Tester read the temperature use 12bit resolution, it first starts a “Convert T“[44h] command, and then series reads

the 9 bytes of the “SCRATCHPAD” and the “64-BIT LASERED ROM”. Fetch the first two byte within the “SCRATCHPAD” converts this first two bytes to a readable temperature shown at row 3 of the LCD

 

For example:

Reading of the DS18B20.

Scratchpad :

 

EC014B467FFF0C102A

 

To exit this function press and hold the control knob.

 

15.DHT11

DHT11 is a sensor with temperature and humidity measurement.  The degree of accuracy is +-5%RH and +-2°C

Measures temperatures from 0 to 50C , Measures humidity from 20-90%RH.

When entering to this function, the Row 2 of the LCD will show  “1=GND 2=DQ 3=VDD” , it’s means 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 and the TP3 of the tester is connect to VCC of the DHT11.

The Tester cannot sense the pins of the EHT11 so make sure it is connected as per the prompt.

 

When a correct reading is made, the temperature is shown at row 3 and humidity is show at row 4.

 

Exit this function by pressing and holding the RPEWS > 3s.

 

16.IR_decoder

IR Decoder waiting for a button to be pressed on the remote control.

To use this function an IR module has to be inserted as per the diagram below.

A successful decode is shown on row4 - 8 of the LCD, where row 4 displays the IR protocol (TC9012 or uPD6121).

 

Row5 and row6 display “User code 1” and “User code 2” and row 7 displays the data and the Bitwise NOT of the data(~data).

 

Row8 displays the four byte together.

 

All of the numbers are displayed in hexadecimal.

 

16.IR_Encoder

This function is a simulation of IR Remote Controller. It can drive a IR LED connected at the tester’s PWM output

interface associate with the user input. since the tester can 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 an item.

Row2 of the LCD is the select protocol, like IR Decoder above, there are two protocol for select, ”TC9012” and

“uPD6121”. It can be changed by rotating the control knob, when the “>” appear at row2.

 

Row3 and row4 change the “user code 1” and “user code 2” value by rotating the control knob. Left rotate will decrease and right rotate will increase the value.

Press and hold the control knob for >1S and <3S (>3S will exit this function) will add the value by

0x10 to quickly reach to the chosen value.

 

Row5 changes 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 control knob a “->” will appear

until the transition is completed.

 

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 in frequent use on television in china.

 

17. C(uF)- correction

This function set the correction value for big capacitor measurement Positive values will reduce measurement results.