passingthru
- May 2, 2010
- 3
- Joined
- May 2, 2010
- Messages
- 3
I've been a member of this forum for quite some time, but as I don't play with electronics much my contributions have probly been nil, so although it may seem like I'm just picking brains here I remain a member for an occasion when I may need assistance. I have read through about 14 pages but failed to find suitable information relevant to my issue.
I seem to have an issue that I have not encountered in the past. I make small projects which run on a transformer reducing AC mains power to 24vdc. Included in the circuit is one LED and one resistor. The circuit is completed when two electrodes are submerged in liquid, one electrode is positive and the other is negative.
After completing one of these projects recently I found I was unable to attain my 24vdc across the electrodes. There is a massive drop in voltage, down to around 3v. I have tested the positive and negative on the power adaptor socket with a multimeter and have the correct voltage coming in so the socket is OK, I have tested the circuit between the positive on the socket to the positive side of the LED {which is soldered to the negative on the socket} and that is OK. I have tested the resistor and that is OK. I even unplugged the transformer and put a battery across the terminals of the LED and it lit up fine.
I have bench tested the LED with a 9v battery and it lights up fine {signifying that the LED is functioning as it should, from what I've read anyway} but I can't figure out why it won't allow the 24v to continue past the LED through to the resistor and hence on through to the electrodes? If in fact it is the LED that's causing my problem, I've tested everything else but the failure appears to be at the LED.
The LED is 3mm and I have not struck this problem in the past, I've made numerous projects such as this in the past with no problem. I have purchased these LED's recently. If I've explained my circumstance clear enough in the above, I would be grateful for any assistance which may be forthcoming. I can't fathom what is going on? I've changed LED's and still no resolution. Have I purchased LED's with some form of voltage limit - if that is at all possible?
I seem to have an issue that I have not encountered in the past. I make small projects which run on a transformer reducing AC mains power to 24vdc. Included in the circuit is one LED and one resistor. The circuit is completed when two electrodes are submerged in liquid, one electrode is positive and the other is negative.
After completing one of these projects recently I found I was unable to attain my 24vdc across the electrodes. There is a massive drop in voltage, down to around 3v. I have tested the positive and negative on the power adaptor socket with a multimeter and have the correct voltage coming in so the socket is OK, I have tested the circuit between the positive on the socket to the positive side of the LED {which is soldered to the negative on the socket} and that is OK. I have tested the resistor and that is OK. I even unplugged the transformer and put a battery across the terminals of the LED and it lit up fine.
I have bench tested the LED with a 9v battery and it lights up fine {signifying that the LED is functioning as it should, from what I've read anyway} but I can't figure out why it won't allow the 24v to continue past the LED through to the resistor and hence on through to the electrodes? If in fact it is the LED that's causing my problem, I've tested everything else but the failure appears to be at the LED.
The LED is 3mm and I have not struck this problem in the past, I've made numerous projects such as this in the past with no problem. I have purchased these LED's recently. If I've explained my circumstance clear enough in the above, I would be grateful for any assistance which may be forthcoming. I can't fathom what is going on? I've changed LED's and still no resolution. Have I purchased LED's with some form of voltage limit - if that is at all possible?