UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post

Bazz4CQJ · 24th May 2019, 11:53 pm

I am not 100% clear from your post exactly what you are trying to do, but I can point you at at a circuit which switches a circuit on when the battery volts go below a pre-set threshold https://www.eleccircuit.com/low-volt...itor-by-lm339/ .

I've used this for an alarm, set up so that when a 12V lead acid battery has its voltage fall below about 11V, the comparator switches on the buzzer. I guess the buzzer could be replaced by a relay?

B

24th May 2019, 11:53 pm	#2
Bazz4CQJ Dekatron Join Date: Apr 2009 Location: Oxfordshire, UK. Posts: 4,935	Re: Comparator circuit. I am not 100% clear from your post exactly what you are trying to do, but I can point you at at a circuit which switches a circuit on when the battery volts go below a pre-set threshold https://www.eleccircuit.com/low-volt...itor-by-lm339/ . I've used this for an alarm, set up so that when a 12V lead acid battery has its voltage fall below about 11V, the comparator switches on the buzzer. I guess the buzzer could be replaced by a relay? B __________________ Saturn V had 6 million pounds of fuel. It would take thirty thousand strong men to lift it an inch.