i want to build the circuit posted below which is a soft On/Off circuit and i need some advise. I want the circuit to work from a 4V battery by replacing relay with a bunch of white LEDs so what modifications I need in this circuit to make it work from a 4V battery? Also is there any fault in the circuit? The IC is flip flop CD4027. All kind of infos will be greatly appreciated
You should not leave pin #4, floating, also assuming a current gain of 10 in the transistor, the 8k2 is far to high a value, you only have 1mA Base current.
There should also be a back EMF clamp diode across the relay coil.
Check the CD4027 Source current drive specification ref image
Yes Jp...just a push and the circuit should turn ON and turn off by next push..i'm not talking about the mechanical switch because mechanical switch makes the LEDs flick as the current drops in the battery..so i want use an electronic switch..any simple circuits that you could recommend? Thanks jp
Thanks eric so i should set the pin high or low and change the resistance to low and put a diode to prevent back emf but i don't use relay in this circuit actually its to turn On/Off some white LEDs..maybe 5 of them. Is there anything else i should aware regarding this circuit? I'm gonna build that soon if everything else is ok..don't wanna waste time by making mistake and burn them that's why i need your help thanks jp and eric
The unusal IC is not needed and the circuit does not need Schmitt-trigger inverters. An ordinary CD4069 has six Cmos inverters and it works with a supply down to 3V: