ASCEL Electronic AE20204 Installation and operating instructions

Æ20204 LC METER
Assembly and
Operation Manual

REV 3.0 EN
© 2014 Ascel Electronic

Table of Contents
Safety Information.....................................................................ii
Handover of a Device Built From a Kit....................................iv
Intended Use.............................................................................iv
ESD Warning.............................................................................v
AE2 2 4 LC METER................................................................1
Circuit Description.....................................................................2
Soldering....................................................................................5
Component Reference................................................................7
Assembly..................................................................................15
Troubleshooting Checklist.......................................................18
Power Supply...........................................................................2
Case Mounting.........................................................................21
Operation..................................................................................22
Circuit Diagram.......................................................................25
Bill of Materials.......................................................................26
Component Placement.............................................................28
Data Interface...........................................................................29
Specifications...........................................................................32
i

Warning
Please read this manual before you assemble and use this it.
Keep it accessible for all users at all times.
Safety Information
Know and follow the applicable regulations for
electric devices in your region. In Germany,
these are especially VDE 0100, VDE
0550/0551, VDE 0700, VDE 0711 and VDE
0860. Pay attention to the following safety
advices:
• Disconnect the power supply before opening the case.
• Wor on devices only if you made sure that they are
disconnected from any power supply, and any possible charge
inside is discharged.
• Devices must only be used if they are mounted in a case in a
way that prevents the user from touching any live wires or
parts. Disconnect the device from its power supply during
assembly.
• Always chec the power cords for brea s or damaged
insulation. Replace any defective parts immediately.
• See advice from a qualified expert if you are not sure about
any specific value of a part, an installation procedure, or how
to connect accessories.
ii

•Always chec if the device is suitable for the intended purpose
before putting the unit in use. See assistance from a qualified
professional or the manufacturer if you are not sure.
• The manufacturer assumes no liability for errors made during
assembly or operation.
• Devices that need a supply voltage greater that 24V may be
assembled by professionals only, to avoid hazards from
improper assembly.
• In schools, educational institutes or wor shops, the use of this
unit must ta e place under the supervision of qualified staff.
• Do not put this unit in use in an environment where the ris of
fire or explosion or explosive gas, vapor or dust is present.
• If the unit must be repaired, use original parts only. The use of
inappropriate parts may lead to a safety ris .
• Avoid wor ing alone.
• Keep electronic parts away from children.
• Do not replace parts with such that does not meet the required
parameters. For example: never replace a fuse with another one
with higher nominal current!
• Other regulations may apply. Please chec the local safety
regulations for assembling electronic devices.
iii

Handover of a evice Built From a Kit
(in countries where applicable)
If you hand over a device built from a it, you legally become
the manufacturer. This means you are responsible for
complying with the appropriate regulations for electronic
devices. All accompanying papers, in particular this manual,
must also be passed over. Where necessary (for example in the
European Union) you must also publish your identity to the
consignee.
Intended Use
(in countries where applicable)
The intended use of this device is measuring the values of
capacitors and inductors.
• Other uses are not approved!
iv

ES Warning
What is ESD?
ESD (Electrostatic Dis-
charge) is the sudden flow
of electricity between two
objects caused by contact
or an electrical short. It
can reach very high voltages of many V. In some cases even
over 100 V!
Causes of ESD
The main cause of ESD events is static electricity. Static
electricity is usually generated through tribocharging, li e
wal ing on a rug, ascending from a fabric seat, removing some
types of plastic pac aging or using non-ESD compliant tools.
Danger of ESD
The high voltage pulse can easily destroy electronic parts. ICs
and FETs are very sensitive to high voltage. Even a short,
single touch may destroy a part!
How do I prevent damage due to ESD?
Always ground yourself while wor ing with electronic parts. A
grounded conducting wrist strap and proper anti-static wor
surface mat will help prevent ESD damage. Also ma e sure
that the soldering iron is grounded and ESD-safe.
v
Warning symbol for an
electrostatic sensitive device

AE20204 LC METER
The AE20204 LC Meter allows the measurement of
capacitance and inductance of passive components,
particularly very small values, even below 1 pF / 1 µH. The
resolution thereby is 0.01 pF (10 fF) / 10 nH. It is an invaluable
aid for amateur radio enthusiasts, as well as anyone engaged in
electronics.
The RS232/USB interface1 allows the included software to
access the readings and show them on screen. Logging is also
supported. The easy, plain text command protocol allows
simple integration with external tools and systems.
All SMD (Surface Mounted Device) components are already
soldered, so the it is also suitable for beginners in electronics.
The comprehensive manual should help answer all questions
that may arise during assembly.
Please read the complete manual (especially if you are not yet
experienced in electronic engineering) before building the it.
1USB optional
1

Circuit escription
To measure capacitance and inductance, the AE20204 LC
Meter uses an oscillator composed of IC2, C7, C8, C9, L1, R2,
R3, R4, R5 and R9. The tested capacitor is switched in parallel
to C9 to measure capacitance. The tested inductor is switched
in series to L1 to measure inductance. This lowers the
oscillator's frequency.
The microcontroller IC1 is used to measure this frequency and
calculate the value of the tested capacitor or inductor. The
value is displayed on the LCD and output to the RS232/USB
interface. T1, R8, R10 and R1 provides the correct voltage
levels for the RS232 interface. IC4, C13, C14, C15, C16, R12
and R13 implements the USB interface.
Note: with the USB model, the UART-to-USB-Bridge FT23 XS
(IC4) is pre-assembled.
The positive regulator IC3 provides the 5V voltage for the
device. C4, C5 and C11 are bypass filters, D1 is an input
protection diode.
The relay K2 switches the input between series and parallel
connection, which selects capacitance or inductance
measurement. K1 is used to switch the precision capacitor C10
to the oscillator. D2 and D3 are flybac diodes for the relays.
The LC meter requires no calibration as it uses a precision
0.5% tolerance reference capacitor (C10) to determine the
exact values of the capacitor and inductor (C9 and L1) that
forms the oscillator. The method is described below.
2

First, the frequency without C10 is measured (f1).
f1=1
2⋅π⋅
√
L1⋅C9
Then, the frequency f2 is measured with C10.
f2=1
2⋅π⋅
√
L1⋅(C9+1000pF)
C9 can be obtained by equalizing both equations.
C9=f22
f12−f22⋅1000pF
Since C9 is nown now, L1 can be calculated.
L1=1
4⋅π2 ⋅f12 ⋅C9
This self-calibration is performed on start-up. To measure
components, frequency f3 is obtained with the component
under test connected to the oscillator. The un nown
capacitance Cx or inductance Lx can be calculated as follows:
Cx=[ f12
f32−1]⋅C9
Lx=[ f12
f32−1]⋅L1
This method allows the measurement of very small values, for
example the capacitance of cables.
3

Note: the values of real capacitors and inductors are not
constant, but depends (amongst others) on frequency.
Measuring with different test frequencies will give different
results!
Note: electrolytic capacitors can not be measured with this
device.
Note: the quality factor of the inductor must be sufficient to
allow oscillation on test frequency.
4

Soldering
Please read the following pages if you are not yet experienced
in soldering. Good soldering is a matter of practice! Practice on
old boards until you feel confident before assembling the it.
• The parts are mounted on the silkscreen side of the PCB.
Except parts whose designators ends with an asterisk like
S1*). These are mounted on the other side!
• Do not inhale the fumes from the flux! Wash your hands
after soldering! Wear protective glasses!
• If you use additional flux, ma e sure it is suitable for
electronics use! Non-suitable flux may contain acid which will
damage the traces on the PCB over time.
• Try to solder fast. Heating up for too long may damage the
components and the board.
• Solder wire with a diameter between 0.5-0.75mm (0.02"-
0.03") is most suitable for through-hole components. Lead
solder is easier to use than lead-free solder.
• A clean, non-oxidized tip is essential for good soldering. Use
a wet sponge or a metal wool tip cleaner to regularly clean the
tip. The metal wool cleaners are superior to a wet sponge as
there is no temperature shoc .
5

• When soldering active components (ICs, Transistors,
LEDs...), it is very important to prevent overheating the
components. They should be soldered in no more than about 5
seconds. In addition, it is important not to confuse the polarity!
See the next chapter on individual component types and their
correct orientation.
• To solder:
1. Use the tip of the soldering iron to simultaneously heat
up the PCB and the component leg.
2. Add solder. It should melt around the component leg.
3. Wait a moment. Then remove the iron.
4. Do not move the part you just soldered for a few
seconds while it is cooling down. Moving it may cause
the solder joint to crac . With lead solder, the solder
joint should be glossy.
5. After soldering, use side cutters to cut the leads
straight above the solder joint.
• After you are finished, chec all components for correct
placement and orientation. Also, chec for unintentional shorts
on the board. Small solder leftovers may cause shorts which
can damage the board or the components.
• Use isopropyl alcohol (IPA) or a specific PCB cleaner fluid to
remove flux residues. Flux is corrosive and should not remain
on the board.
6

Component Reference
1 Resistors
To save PCB space, the resistors are mounted standing. To
install:
1. Bend the leads in form and put the
resistor through the corresponding
mounting holes.
2. Bend the leads aside to prevent the
resistor from falling out.
3. Solder it accurately on the bac
side.
4. Cut the remaining leads above the solder joint.
The resistance value is given with colored bands on the
resistor. The code consists of four, five or six bands. With four
bands, the first two are the base value (see table below), the
third is the multiplier to the base value and the fourth is the
tolerance. Five-band code uses the first three bands for base
value. With six bands, the sixth is the temperature coefficient.
The resistor value is:
base value * multiplier [ ± tolerance ]
There are two possible arrangements for the bands order:
7
Type A Type B

Color Codes:
Color Digit Multiplier Tolerance ± in %
None - - 20
Silver - 10-2 10
Gold - 10-1 5
Blac 0 100-
Brown 1 1011
Red 2 1022
Orange 3 103-
Yellow 4 104-
Green 5 1050.5
Blue 6 1060.25
Purple 7 1070.1
Grey 8 1080.05
White 9 109-
2 Capa itors / Ele trolyti Capa itors
Capacitors are soldered the same way as resistors. Electrolytic
capacitors are polar. They must be mounted in the correct
orientation! They will be destroyed when installed in
reverse polarity and may even burst!
Please eep in mind that different manufacturers mar the
polarity in different ways. The mar ing may represent the
positive or the negative terminal! The actual polarity (+ or -) is
printed inside the mar er band that points at one of the leads.
8

Capacitance Identification
A three-digit number without letters is the capacitance in pF,
calculated this way:
a∗10b
where
a
are the first two digits
and
b
is the third digit (105 become 10*105 pF = 1µF). One-
or two-digit numbers states the capacitance directly in pF. A
number including the letter "n" is the capacitance in nF, where
3n9 is 3.9nF.
Upper-case characters denote the tolerance according to this
table:
B C D F G H
±0.1pF ±0.25pF ±0.5pF ±1% ±2% ±2.5%
J K M S Z P
±5% ±10 ±20 +50%
-20%
+ 80%
- 20%
0%
-10%
A number following up indicates the electric strength.
Sometimes you may encounter a number li e 0.5, this is the
capacitance in µF.
Electrolytic capacitors are usually labeled with the capacitance
in µF straight. µ is where the decimal point is: µ33 is 0.33 µF,
3µ3 is 3.3µF and 33µ is 33µF.
9

3 Diodes
The circular band on diodes identifies the cathode (negative
terminal). The bar depicts the cathode in the symbol. The
positive terminal is called the anode.
Diodes are mounted horizontal. Try not to heat up the body of
the diode while soldering.
4 LEDs
LEDs (light-emitting diodes) must be soldered with respect to
the correct polarity as well. The cathode is identified by the
short lead and the larger electrode inside.
1

5 IC-So kets / ICs
With ICs (integrated circuits), it is essential to observe correct
polarity. Most ICs will be damaged or destroyed when mounted
incorrectly. The mar on the sil screen must match the notch
on top of the IC.
Pin numbers are counted counter-cloc wise, starting from the
notch.
Note: Please also pay attention to the ESD warnings at the
beginning of this manual. ICs are ery ESD sensiti e, they
can be destroyed e en by a minor electrostatic discharge
e ent!
11

6 Transistors
Transistors must be mounted in the correct orientation. The flat
side of the transistor must match the correspondent side in the
sil screen drawing. The leads may not cross.
Note: field-effect transistors (FETs) are extremely
sensitive to ESD.
7 Crystal
The polarity of the crystal is not relevant, but the bottom side
of the pac age is conductive. To prevent shorts, the crystal
should be mounted with a little distance to the board see
the image on the next page).
12

8 Indu tors
Inductors are soldered just li e resistors. They also use similar
color-coding, usually with four bands. The first two are the
base value (see table below), the third is the multiplier to the
base value and the fourth is the tolerance. The inductor value
is:
base value * multiplier [ ± tolerance ]
Color Codes:
Color Digit Multiplier Tolerance ± in %
None - - 20
Silver - 10-2 10
Gold - 10-1 5
Blac 0 100-
Brown 1 1011
Red 2 1022
Orange 3 103-
Yellow 4 104-
Green 5 1050.5
Blue 6 106-
Purple 7 107-
Grey 8 108-
White 9 109-
13