Indeed it is nice and simple however can be a bit slow to respond. mind you I have about a zillion applications open on my machine and with 3GB of Ram still running out of memory .
Probably havent rebooted in 2-3 weeks.
Please note that I memorised the diagram which helped a lot .
I haven't seen the original blue epoxy-fiberglass Veroboard for years. It was unbreakable.
The tan-coloured phenolic stuff warps and breaks easily.
I use epoxy-fiberglass "Veroboard" from China now.
The original epoxy-fiberglass Veroboard was a dark blue colour. The sheets were about 50cm long and about 10cm wide (34 strips).
I looked for a pic in Google Images but couldn't find one.
The original epoxy-fiberglass Veroboard was a dark blue colour. The sheets were about 50cm long and about 10cm wide (34 strips).
I looked for a pic in Google Images but couldn't find one.
Consider you have an LED with a 2Vdp and you want to run it from a 9Vdc supply.
This means you must drop 7V in a series resistor.
You say you want 20mA thru the diode [ I would suggest thats to high for a 9Vbty]
anyway Rseries = 7V/0.02 = 350R say 390R
For 10mA Rs = 7/0.01 = 700R say 680R
Do you follow OK?
EDIT: You only need one resistor.
If you must have a 20mA LED [wasteful for the battery] the use a 390R
I am using a push button, with an LED, I know it might be an additional drain on the battery, but I am not too worried about this for now, I may not need the switch nor the LED later on.
Consider you have an LED with a 2Vdp and you want to run it from a 9Vdc supply.
This means you must drop 7V in a series resistor.
You say you want 20mA thru the diode [ I would suggest thats to high for a 9Vbty]
anyway Rseries = 7V/0.02 = 350R say 390R
For 10mA Rs = 7/0.01 = 700R say 680R
Do you follow OK?
EDIT: You only need one resistor.
If you must have a 20mA LED [wasteful for the battery] the use a 390R
I am using a push button, with an LED, I know it might be an additional drain on the battery, but I am not too worried about this for now, I may not need the switch nor the LED later on.
No Unfortunately I got the 2.2VDC one which does not have a resistor.
Although I had a choice of either, but I thought the 12VDC one will not work on my 9VDC battery, now thinking about it I think it would have been perfect.
I tried both the 390R and 680R and both seem to work. I am thinking that the 680R is better to use but I do not know which one will put more strain on the battery though.
I tried both the 390R and 680R and both seem to work. I am thinking that the 680R is better to use but I do not know which one will put more strain on the battery though.
Indeed. I did not notice a clear visible difference in brightness between the two resistors.
I will certainly go with 680R in this case.
Ohms law is not a problem but rather using it with the correct figures is
Thanks a lot.
I am making a complete enclosed PCB with bananna connectors and USB connector and p/b with LED.
Bananna for the clamp which uses them.
USB for the output and +v input.
and push button to switch on/off .
Almost there .
By the do you recommend using single or multicore cable connectors for the Veroboard? I was thinking of using the phone cables that are single core but the color does not help, I do have multicolored multicore cable but I am reluctant to use it becuase it is normally used for audio (I think). So I ordered single core cable but until it arrives I am twiddling my thumbs
By the do you recommend using single or multicore cable connectors for the Veroboard? I was thinking of using the phone cables that are single core but the color does not help, I do have multicolored multicore cable but I am reluctant to use it becuase it is normally used for audio (I think). So I ordered single core cable but until it arrives I am twiddling my thumbs
hi,
For the light current, low voltage work phone wire or multicore is OK.
I have old multicore cable 7/0.2mm which I strip off the outer overall pvc sheath and screened braid, that I use for wiring from switches, banana,batteries, plugs etc.
For pcb board links single core [phone] wire is best.
Your vision's response to brightness is logarithmic to allow you to see a wide range from the light from a candle to sunlight. Therefore an LED's brightness does not look much different when its current is halved or doubled.
Your 9V battery measures "only" 8.23V when it is loaded because it is running down.
A 9V battery doen't have much power. Look at its datasheet from the website of a battery manufacturer like Energizer:
1) It is 9.0V when new.
2) With a 27mA load its voltage drops to 8V in about 1 hour.
3) Its voltage drops to 7V in about 7 hours but then the current is less.
4) Its voltage drops to 6V in 22 hours but then the current is very low.
Thanks. I will consider adding an external power adaptor.
As it stands this will not be running for long time. Having said that I would not mind finding out the actual total load on the battery once all have been put together, and have a test run until battery runs out and see the impact on the AD736 and CA3140 outputs.
Your vision's response to brightness is logarithmic to allow you to see a wide range from the light from a candle to sunlight. Therefore an LED's brightness does not look much different when its current is halved or doubled.
Your 9V battery measures "only" 8.23V when it is loaded because it is running down.
A 9V battery doen't have much power. Look at its datasheet from the website of a battery manufacturer like Energizer:
1) It is 9.0V when new.
2) With a 27mA load its voltage drops to 8V in about 1 hour.
3) Its voltage drops to 7V in about 7 hours but then the current is less.
4) Its voltage drops to 6V in 22 hours but then the current is very low.
I've been going over the circuit of the CA3140 to amplify the AD736 signal and I drew a blank on how the cicuit below was decided upon (Please ignore question in the image ):
What I would like to understand is why did we go with a 4k7 resistor at pin2 and Why the 10k at pin 3.
I understand the voltage at 4k7 will be 4.5v so applying a 4700 ohm resistance will generate 0.96mA.
And for pin 3 at a maximum of 1VDC we get 0.1mA.
So what is the significance of choosing those particular ones as opposed to say 10k at 2 and 20k at 3 for example, how would this have impacted the output. For instance.. would i get the same results provided i adjust the 20k VR correctly?