I wish everyone would put pictures or diagrams in their questions. Show 8 more comments. Active Oldest Votes. I was wondering why one was brighter than the other. I thought it was because the forward voltage from the LEDs.
So the reason for this is due to the way I set up my original schematic? In schematic 2, the resistor supplies the same current to both LEDs. Okay well now I am really confused because why the hell are my LEDs lighting up at all then? The current would pass through the LED before the resistor.
Is current flowing in a different direction. Maybe I should just scrap this. This is an excellent circuit to play with to discover all sorts of things that I take for granted as intuitive, and you have yet to learn. Measure voltages round your circuit.
Build both my circuits, and measure voltages round those. You can do that with a simulator as well, but it's so much more visceral with LEDs and meters. Show 4 more comments. Sign up or log in Sign up using Google. Sign up using Facebook. Sign up using Email and Password. Due to its 10 year lifespan, this 9-volt battery is the first option of major smoke alarm manufacturers for their premium lines of year ionization smoke alarms.
When it comes to modern smoke alarms, they must use year batteries , which is both good and bad. Because batteries need to be replaced so rarely and so easily, the year lifespan is deemed acceptable by fire prevention firms. Smoke alarm batteries are should replaced hand handled with great care for us, as a home safety blog because we value your safety. There is no harm in being cautious, however. Battery replacement is recommended once or twice a year for smoke detectors even if 10 years is indicated on the product.
Some people make a yearly habit out of this by doing it on new year, their birthday or on Christmas. The best 9 volt batterie s in this article are available for purchase, so stock up on them and replace them as soon as possible. For your own peace of mind! Most of the cheap smoke alarms use 9-volt batteries that last for one to two years.
As an alternative, a decent quality 9-volt battery detector should have an expected lifespan of at least 10 years. Even though 9-volt batteries are widely available, and typically cheaper if purchased in quantity, the vast majority of smoke alarms still utilize them.
A 9-volt battery, on the other hand, is easy to find in any store and is quite reliable, as well as being one of the most cost-effective solutions in the long term. These batteries are created differently, using different materials, which has an impact on their functionality in diverse applications.
Most typical electrical gadgets use alkaline batteries, which last longer than other types of batteries. PM me or respond here as others may want to know how to calculate this. Ryan in CA. NOLAfishwater is not taping much these days 72 Needs to get out more Check the mAh rating on your battery and divide by mA to get hours.
So, if your 9V battery is rated at mAh and your device draws at a maximum of 25mA, then your battery would last 24hours in theory. You can always do a dry run to confirm how long your rechargeables will last. Church-Audio 44 Needs to get out more Posts: Gender:. I have no idea what 9V rechargeables are rated at.
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