Electronics > Beginners
Sources for 3 Vdc
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fixit7:

--- Quote from: Audioguru on June 09, 2019, 01:22:28 am ---This site is a nightmare to find posts by people. On all other sites I simply click on your profile.
I found your Laser Alarm Project but many of your photos were not posted here, instead you posted them over at Drop Box who deleted them.

Guess what? Your schematic shows an IC with no part number. It is probably an ordinary old LM555 or NE555 that does not work if its supply is less than 4.5V.
Your 3V battery will drop to 2V.

--- End quote ---

It was a ne555. I abandoned that and found a better design.

It uses a S8550 transistor instead of the ne555.

See this post.

https://www.eevblog.com/forum/beginners/circuit-stopped-working-when-transferred-to-breadboard/
Audioguru:
Since you were not using the NE555 timer as a timer I said last month that it was simply a transistor.
Your new circuit has no schematic so I do not know if it is correct. If it is correct then its current at 3V will be less than 10mA when it is beeping and less when not beeping.
fixit7:

--- Quote from: Audioguru on June 09, 2019, 01:43:55 pm ---Since you were not using the NE555 timer as a timer I said last month that it was simply a transistor.
Your new circuit has no schematic so I do not know if it is correct. If it is correct then its current at 3V will be less than 10mA when it is beeping and less when not beeping.

--- End quote ---

Thanks.

I am redoing the circuit as I soldered on the wrong side.

When I finish, I will actually measure the actual current used.

It currently uses 2 AA batteries. I would like it to last at least a year before changing out the batteries or using some NiMh ones that I already have.

Andy
ArthurDent:
1) The LMC555 (CMOS) version of the regular 555 timer is designed to work down to 1.5 volts at very low power.
2) please reread and understand what many have been telling you about no battery lasting close to the time you say you want.

This CMOS 555 circuit may have some useful info. It can flash an LED for up to 6 months on two AAA batteries.
https://www.allaboutcircuits.com/textbook/experiments/chpt-8/cmos-555-long-duration-minimum-parts-red-led-flasher/
fixit7:

--- Quote from: ArthurDent on June 10, 2019, 02:57:22 am ---1) The LMC555 (CMOS) version of the regular 555 timer is designed to work down to 1.5 volts at very low power.
2) please reread and understand what many have been telling you about no battery lasting close to the time you say you want.

This CMOS 555 circuit may have some useful info. It can flash an LED for up to 6 months on two AAA batteries.
https://www.allaboutcircuits.com/textbook/experiments/chpt-8/cmos-555-long-duration-minimum-parts-red-led-flasher/

--- End quote ---

It uses a S8550 transistor instead of the ne555.
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