LC Meter DIY KitLC Meter DIY KitLC Meter DIY KitLC Meter DIY Kitby Phil Rice VK3BHRby Phil Rice VK3BHRby Phil Rice VK3BHRby Phil Rice VK3BHR

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Components List:Components List:Components List:Components List:

Resistors:Resistors:Resistors:Resistors:

R1 5% Carbon Film Resistor 3K (orange, black, red, gold)

R2, R3, R4 5% Carbon Film Resistor 100K (brown, black, yellow, gold)

R5 5% Carbon Film Resistor 20K (red, black, orange, gold)

R6 5% Carbon Film Resistor 47K (yellow, violet, orange, gold)

R7, R8 5% Carbon Film Resistor 4.7K (yellow, violet, red, gold)

R9, R10, R11, R12 5% Carbon Film Resistor 1K (brown, black, red, gold)

R13 5% Carbon Film Resistor 36R (orange, blue, black, gold)

P1 10K Potentiometer Trimmer (103)

Capacitors:Capacitors:Capacitors:Capacitors:

C1, C7, C11, C12 100nF Multilayer Ceramic Capacitor (104)

C2 220uF Electrolytic Capacitor 16V

C4 100uF or 220uF Electrolytic Capacitor 10V

C3, C6 1nF 5% Polyester Film Box Capacitor (102)

C5, C8 10uF Tantalum Capacitor

C13, C14 30pF Multilayer Ceramic Capacitor (300)

Inductors:Inductors:Inductors:Inductors:

L1 100uH Radial Inductor

Semiconductors:Semiconductors:Semiconductors:Semiconductors:

T1 2N3906 PNP Transistor

PIC16F628A Micro-controller flashed with hex

LM7805 5V Positive Voltage Regulator

D1 1N4007 Diode

D2 1N4148 Diode

LED 3mm Red

Other:Other:Other:Other:

LCD 16x2 HD44780 Compatible

5V Relay

4.000 MHz Crystal

S1 Slide Switch Button On/Off

S2 Tact Push Button Zero

S3 DPDT Push Button C/L

18 Pin IC Socket

12 Pins Male Header 21mm (6+6)

2 Pins Male Header

2 Pins Single Male Header Right Angle

8 Pins Double Male Header Right Angle

6 Pins Female Header DIP SIP Adapter

2.54 mm Jumper Cup

2x 15mm M2.5 Standoff

4x M2.5 Screw

4x M3 Screw

4x M3 Standoff

Technical Specifications:Technical Specifications:Technical Specifications:Technical Specifications:

Capacitors Measuring Range: 0.1pF to 0.1uF

Inductance Measuring Range: 0.01uH to 20mH

Accuracy: 1%

Supply Voltage: 9V regulated DC

Supply Current: 63mA

Software Calibration with a good external capacitor.

Compact PCB Design

Dimensions: 50 x 85 x 35 mm

Background:Background:Background:Background:The original circuit and hex file was developed by Phil Rice VK3BHR. You can find more

information about this open source project at his website:

https://sites.google.com/site/vk3bhr/home

I would say many thanks to him for the LC Meter circuit and hex because I use it at my home

lab more than 2 years with many different projects. I designed my own PCB and produced DIY

kits to help others ham's like me to build this good LC Meter at home. The kit should be used

with 9V 200mA regulated power supply and not with 9V battery! It has high power

consumption (about 63mA) because of the relay type I used and LCD backlight.

The assembling process require solder skills. Full kit soldering with calibration can take a

hour or two if you are beginner in electronics. So please take your time, print the circuit page

and put in in front of your eyes during soldering. The PCB has silkscreen with components

numbers. It always hard to unsolder components if you made a mistake, that's why I advise

double check every component and it's direction before you'll solder it to the PCB. All

components are through-hole and are easy to solder.

Calibration process is simple. It will be described later in the manual. You will need some

precision capacitor with 1% accuracy.

The kit can be used without enclosure, but you can use any small size plastic box for this

project. The PCB has 2 pins for external probes connection. Solder your probes terminals with

short wires to this pins.

The LCD color of the kit is random. Usually I'll send you Blue Color, depend on stock. Any

HD44780 compatible 16x1 or 16x2 display will work fine.

Assembling and Soldering:Assembling and Soldering:Assembling and Soldering:Assembling and Soldering:

Remember do clean solder work and install right components in the right place, because it

always hard to unsolder the components from the PCB. We cannot be responsible if you'll

overheat your PCB or will damage the kit components during wrong soldering with a

mistakes. So please double check yourself before you solder. Remember to use a solder with

Rosin Core Flux. Some industrial flux has several Mega-ohms resistance and they require a

special cleaning that cannot be performed at home.

Do not use too much solder. A good joint should look like:

Extra flux can be cleaned after with soft brush and medical alcohol. We advice you to use

0.8mm or 1.00mm thickness solder wire with low melt point:

60/40 186 Celsius (386 Fahrenheit)

63/37 183 Celsius (361 Fahrenheit)

If you'll need to remove excess solder from the pad, use desoldering tools (braid wick or small

pump).

Start your soldering with horizontal components, i.e. resistors, diodes, IC socket, crystal etc.

Fill with a solder 10 PCB links pads (there is 2 links close to C4 on the photo you can see and

their pads are filled with solder).

Remember about tantalum and electrolytic caps polarity!

Put special attention to PIC chip direction! There is the finished PCB before LCD connection:

Double row right angle pins should be installed in up-side down position. This pins are used

for calibration and internal oscillator frequency control.

Hardware installation: use 4x M3 standoffs for PCB and 2x M2.5 standoffs for LCD board.

Trim the P1 potentiometer as in the photo before you'll connect the LCD. P1 control LCD

contrast. You can recalibrate it a little with a small pliers when the LCD is installed, but do it

carefully!

The finished LC Meter kit with LCD installed:

Please do not solder the LCD if you still not checked that the kit is power up without any

problem. You can gentle push forward the LCD board to provide good contact between LCD

board and 6+6 pins. Solder the LCD board later after you will end all calibration and testing

process.

Connect 9V power supply. Never just wrap a simple wires over the voltage pins. Use only

2.54 mm red and black jumper wires for PSU connection!

The display will say Calibrating and C=0.0pF if the device in capacitance range. Press S2

zero button before measuring. You can toggle S3 DPDT button any time for selecting between

capacitance or inductance range.

Close L/C jumper when in inductance range and press S2 zero button. Remove L/C jumper

before measuring coils. The display will say Over Range when no coil is connected.

Oscillator Frequency:Oscillator Frequency:Oscillator Frequency:Oscillator Frequency:

Connect pin 8 of the PIC to the ground with JMP 2. You should see the oscillator frequency on

the display 50000 +/- 10%

If you'll connect pin 9 of the PIC to ground with JMP 1 you should be near to 71% +/- 5% of

your 50000 +/- 10% frequency.

If you got similar values displayed it mean your LC Meter is soldered and work properly. If not,

please check your soldering.

Calibration:Calibration:Calibration:Calibration:

Connect a good 1% capacitor and adjust the readings with JMP3 and JMP4. When you put

jumper cup on JMP3 or JMP4 contacts it will slowly lower or raise the capacitance reading. You

can use any 1% cap from 100pF to 10nF. When you calibrate the capacitance, the inductance

will be calibrated by auto. You can re-calibrate your device again in any time you'll need.

Support request requirements:Support request requirements:Support request requirements:Support request requirements:

Send your request to support@radiohobbystore.com Please describe your problem,

attach screenshots or pictures and tell what you already tried to do for resolving the

problem.

Attach two clear focused photos of your soldered kit, from both sides of the PCB.

Please wait up to 24 hours for the response.

Please follow our support instruction because we can help you only if you'll work with

support team. If you'll not provide a information for support team we'll not be able to

resolve the problem.

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