background image

Supply voltage (V) - led voltage (V)

required current (A)

= series resistance (ohms)

required current (A)

= series resistance (ohms)

Required resistor power handling= 
voltage over resistor x current passed trough resistor

9V - 1.7V

0.005A

= 1460 ohm

9V -  (3 x1.7V)

0.005A

= 780 ohm

(9V - 1.7V) x 0.005A = 0.036W

closest value : 

use a 1k5 resistor

use an 

820 ohm resistor

a standard 1/4W resistor 

will do the job

Supply voltage (V) - (number of leds x led voltage (V))

How to Calculate the series resistor:

Example: operate a red led (1.7V) on a 9Vdc source.  
Required led current for full brightness: 5mA (this can be found in the datasheet of the led)

LEDs in series:

Example: 3 x red led (1.7V) on 9V battery 
Required led current for full brightness: 5mA 
(this can be found in the datasheet of the led)

Leds feature a speci

fi

 c voltage 

drop, depending on type and 
colour. Check the datasheet for 
exact voltage drop and rated 
current !

Never connect leds in parallel 

Leds and how to use them

An open collector output can be compared to a switch which switches to 
ground when operated

Example: How to switch an LED by means of an open collector output

open collector outputs

Содержание KA04

Страница 1: ... BLY LY L BLY MBLY BLY M MAN MAN MA MAN AN AN AN AN AN AN N MAN AN MAN MAN MAN MA MANU U U U UA U UA UA UA UA UAL U UA UA U UA AL HKA0 KA KA0 A0 A0 A0 A0 A0 A0 0 A0 A0 HK KA0 A04 4 4 4 4 4 4I 4IP P 4 4IP 4 4I 4 1 KA04 KA04 Ethernet shield Ethernet shield for Arduino for Arduino Features For use with Arduino Uno Arduino Mega Based on Microchip ENC28J60 IEEE 802 3 compatible Ethernet controller Inte...

Страница 2: ...Forum Forum Participate our Velleman Projects Forum Subscribing our newsletter visit www vellemanprojects eu ...

Страница 3: ...Velleman N V Legen Heirweg 33 9890 Gavere België ...

Страница 4: ...ers A basic range is fine For some projects a basic multi meter is required or might be handy 1 2 Assembly Hints Make sure the skill level matches your experience to avoid disappointments Follow the instructions carefully Read and understand the entire step before you perform each operation Perform the assembly in the correct order as stated in this manual Position all parts on the PCB Printed Cir...

Страница 5: ... 5 DO NOT BLINDLY FOLLOW THE ORDER OF THE COMPONENTS ONTO THE TAPE ALWAYS CHECK THEIR VALUE ON THE PARTS LIST ...

Страница 6: ...ON I Ceramic capacitors 2 c c X1 25MHz Chrystal 3 C1 100nF 104 C2 100nF 104 C3 100nF 104 C4 100nF 104 C10 100nF 104 C R C7 15pF 15 C8 15pF 15 SW1 Reset Push button 4 Voltage regulator 5 M3 NUT TRANSISTOR M3 BOLT PCB VR1 LD1086V33 IC socket 6 IC1 28p IC1 14p 2 x 6p Do not cut the Do not cut the connector pins connector pins Female header 7 Watch the position Watch the position of the notch of the n...

Страница 7: ... 7 Construction Electrolytic capacitors 8 Watch the polarity C5 470μF C6 10μF C9 470μF 2 1 SK6 2 x 3p 3 Solder LAN connector 9 SK5 IC 10 Watch the position of the notch IC1 ENC28J60 I SP IC2 74HC125 ...

Страница 8: ... 8 Connection diagram CONNECTION DIAGRAM II DOWNLOAD SAMPLE CODE FROM KA04 PAGE ON WWW VELLEMAN BE RESET 2 RJ45 LAN CONNECTOR 1 ICSP CONNECTOR 3 ...

Страница 9: ...28J60 IC1 TX 1 TXc 4 TX 2 RX 3 RXc 5 RX 6 LD GREEN 11 LD GREEN 12 LD YELLOW 9 LD YELLOW 10 SHIELD 8 RJ45LAN V SK5 LEDA LEDB TPOUT TPOUT TPIN TPIN 270 R6 270 R7 LEDA LEDB GND TPIN TPIN TPOUT TPOUT 47 R1 47 R2 18 R3 47 R4 47 R5 100n C1 100n C2 V3 3 GND TXc TXc GND GND GND GND 10μ 100V C6 GND 2K7 R8 GND 25MHz X1 15P C8 15P C7 GND 5V OE1 1 A1 2 Y1 3 OE2 4 A2 5 Y2 6 GND 7 VCC 14 OE4 13 A4 12 Y4 11 OE3 ...

Страница 10: ... 10 PCB ...

Страница 11: ...sistor Example operate a red led 1 7V on a 9Vdc source Required led current for full brightness 5mA this can be found in the datasheet of the led LEDs in series Example 3 x red led 1 7V on 9V battery Required led current for full brightness 5mA this can be found in the datasheet of the led Leds feature a specific voltage drop depending on type and colour Check the datasheet for exact voltage drop ...

Страница 12: ...new Velleman Projects catalogue is now available Download your copy here www vellemanprojects eu Modifications and typographical errors reserved Velleman nv HKA04 IP Velleman NV Legen Heirweg 33 9890 Gavere ...

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