Any electronic people on here?
18 June 2003, 05:25 PM
#1
Scooby Regular
Thread Starter
Join Date: Apr 2002
Posts: 1,010
Likes: 0
Received 0 Likes
on
0 Posts
Hi,
I need a circuit that will basically operate 5 - 7 LEDs when a PLC output is on. So the LEDs have to come on when the plc outputs 5v. Someone said I could use a transistor with the base connected to the PLC output. But I have no idea how to design the circuit for this operation. A 9 volt battery is used for powering the LEDs.
I need a circuit that will basically operate 5 - 7 LEDs when a PLC output is on. So the LEDs have to come on when the plc outputs 5v. Someone said I could use a transistor with the base connected to the PLC output. But I have no idea how to design the circuit for this operation. A 9 volt battery is used for powering the LEDs.
18 June 2003, 05:46 PM
#2
Scooby Regular
iTrader: (2)
Join Date: May 2000
Location: Class record holder at Pembrey Llandow Goodwood MIRA Hethel Blyton Curborough Lydden and Snetterton
Posts: 8,626
Likes: 0
Received 0 Likes
on
0 Posts
your friend is right
Use a BC337 transistor, the base driven by a 1K resistor connected to the PLC o/p. The emitter to ground, the LED's parralelled together (depending on LED type an inline resistor will probably be needed) between 9V and the collector, make sure they point the right way.
A picture is worth a thousand words, well about 30 in this case
Justin
Use a BC337 transistor, the base driven by a 1K resistor connected to the PLC o/p. The emitter to ground, the LED's parralelled together (depending on LED type an inline resistor will probably be needed) between 9V and the collector, make sure they point the right way.
A picture is worth a thousand words, well about 30 in this case
Justin
18 June 2003, 06:05 PM
#3
Scooby Regular
Thread Starter
Join Date: Apr 2002
Posts: 1,010
Likes: 0
Received 0 Likes
on
0 Posts
could i use this transistor:
http://www.maplin.co.uk/products/module.asp?CartID=030618170849890&moduleno=32952&m odulecode=
theres a load there but theres one called BC337-16
http://www.maplin.co.uk/products/module.asp?CartID=030618170849890&moduleno=32952&m odulecode=
theres a load there but theres one called BC337-16
19 June 2003, 07:23 PM
#6
Scooby Regular
Thread Starter
Join Date: Apr 2002
Posts: 1,010
Likes: 0
Received 0 Likes
on
0 Posts
I need 5 LEDs to operate on a 9 volt battery, can this be done? I'm sure I need a reistor, but I have no idea what size. any help?
I have no idea how many LEDs I can run on a 9v battery or what resistor i need. The LEDs will be just a normal cheap red LED.
[Edited by Recaro - 19/06/2003 19:24:16]
edited to see if I could attatch a picture, but it didnt like it.
[Edited by Recaro - 19/06/2003 19:25:14]
I have no idea how many LEDs I can run on a 9v battery or what resistor i need. The LEDs will be just a normal cheap red LED.
[Edited by Recaro - 19/06/2003 19:24:16]
edited to see if I could attatch a picture, but it didnt like it.
[Edited by Recaro - 19/06/2003 19:25:14]
19 June 2003, 09:13 PM
#7
Scooby Regular
iTrader: (2)
Join Date: Mar 2001
Location: Swilling coffee at my lab bench
Posts: 9,096
Likes: 0
Received 0 Likes
on
0 Posts
5 LEDs off a 9V battery has to be done by splitting them into a group of 2 in series and another group of 3. The voltage drop across one LED is 2V, so five in series would require a 10V (minimum) supply.
Assuming a current of 10mA, the group of 3 requires a 300 Ohm resistor and the group of two requires 500 Ohms (the nearest you'll be able to buy are 510, which will make the LEDs slightly dimmer, or 470 which will make them a bit brighter). Join the two groups across the battery in parallel.
Andy.
Assuming a current of 10mA, the group of 3 requires a 300 Ohm resistor and the group of two requires 500 Ohms (the nearest you'll be able to buy are 510, which will make the LEDs slightly dimmer, or 470 which will make them a bit brighter). Join the two groups across the battery in parallel.
Andy.
Trending Topics
20 June 2003, 01:14 PM
#10
Scooby Regular
Join Date: Sep 2002
Location: Fairy Tokens = 9
Posts: 1,951
Likes: 0
Received 0 Likes
on
0 Posts
well 4 leds across a 9 v battery is enough (2v per led) therefore 1v left for approx 15ma would be 1/0.015 = 66 ohms.
or for 10ma its gonna be 100 ohms
Think thats right
or for 10ma its gonna be 100 ohms
Think thats right
Thread
Thread Starter
Forum
Replies
Last Post