Hello All,
I am new to this forum. I was interested in the subject of fuses... Where would you put a fuse on a breadboard? I have built a Johnson cascade counter using a 555 two 4017 s and a 4081 that flash 16 Led s in sequence. My first build I accidently used a low power 555 from RS and when I connected to a 12 volt lawnmower battery it went pffft ( it fried in a picosecond ). I just checked the fuse I have in the red positive cord and its 10 amps ( way too much amperage ). So my question is I would like circuit protection up front but I don't want to keep changing fuses every time I connect to a strong 12 volt battery. The reason for the 12 Lawnmower battery is I have a BDX53c ( 8 amp max ) transistor I want to kick in at some point in my build... The breadboard is only rated at 1 amp and I had the BDX53c in a breadboard next to the breadboard that has 555 etc. Hence when I connected to the 12 volt lawnmower battery yesterday it blew the 10000 uF 25 volt cap, 555 and everything south of that... Plan B ...Today I rebuilt the circuit and I'm using a 9 volt battery to power the 555 etc.. Getting back to my question how do I calculate my fuse.... Here's the list of parts to the circuit... the fuse, a diode, the cap. the 555 etc. ....do I calculate my weakest ( or maybe the cheapest ) part... I will use the 9 volt for the semiconductors on the 1st breadboard and I will use the 12 volt lawnmower battery for the BDX53s and use a barrier strip ( block ) with the 10 amp fuse there... The 555 is configured in Astable mode so there is a 10 nf and a 100nf caps on the 555...the circuit came from looking at different 555 circuits and looking at the data sheet for the 4017 s. I could have started with the lowest rated fuse and work my way up but instead I wanted to find more experienced electronics people and how they would tackle the question...
All the Best
Randy
I am new to this forum. I was interested in the subject of fuses... Where would you put a fuse on a breadboard? I have built a Johnson cascade counter using a 555 two 4017 s and a 4081 that flash 16 Led s in sequence. My first build I accidently used a low power 555 from RS and when I connected to a 12 volt lawnmower battery it went pffft ( it fried in a picosecond ). I just checked the fuse I have in the red positive cord and its 10 amps ( way too much amperage ). So my question is I would like circuit protection up front but I don't want to keep changing fuses every time I connect to a strong 12 volt battery. The reason for the 12 Lawnmower battery is I have a BDX53c ( 8 amp max ) transistor I want to kick in at some point in my build... The breadboard is only rated at 1 amp and I had the BDX53c in a breadboard next to the breadboard that has 555 etc. Hence when I connected to the 12 volt lawnmower battery yesterday it blew the 10000 uF 25 volt cap, 555 and everything south of that... Plan B ...Today I rebuilt the circuit and I'm using a 9 volt battery to power the 555 etc.. Getting back to my question how do I calculate my fuse.... Here's the list of parts to the circuit... the fuse, a diode, the cap. the 555 etc. ....do I calculate my weakest ( or maybe the cheapest ) part... I will use the 9 volt for the semiconductors on the 1st breadboard and I will use the 12 volt lawnmower battery for the BDX53s and use a barrier strip ( block ) with the 10 amp fuse there... The 555 is configured in Astable mode so there is a 10 nf and a 100nf caps on the 555...the circuit came from looking at different 555 circuits and looking at the data sheet for the 4017 s. I could have started with the lowest rated fuse and work my way up but instead I wanted to find more experienced electronics people and how they would tackle the question...
All the Best
Randy