Square Signal

[Inferno]

hello guys..
is there any easy way to get a +12/-12 square signal from a 12 volts battery ??? it should be able to handle about 0.5 A not more...

 

[Inferno]

the frequency should be 1 to 2 Hz

 

[Hero999]

Why?

What exactly are you trying to do?

If all you want to do is flash a lamp then you can buy special relays for that or you could use a 555 timer driving a transistor like the BC549.

 

[Inferno]

i need it to have an 2 outputs... in the first 0.5 seconds..the first output should be 12 volts and the other is zero... in the next 0.5 seconds the first should be zero and the other one is 12 volts....and as i said.. just 0.5 A

 

[things]

what are you trying to make? As hero said, if it's just to flash some lamps, there is already circuits out there for that.

 

[Inferno]

hmm... it s for making a disk coupled on a dc motor rotate in one direction then in an other..

 

[things]

ok, well a simpler way would be to just switch the polarity of the motor, making it spin the opposite way. unfortunately i don't have any circuits in mind at the moment, so maybe someone else can help with this.

 

[Hero999]

You can get h-bridge ICs for that like the L298 or L293 for example.

All you need to do is add an astable 555 timer oscillator running at 2Hz and you've done it.

 

[Inferno]

i ll try looking for the l298... and about the circuit that switch the polarity of the motor... that would br8 and so easy to use ... but me 2 i have no ideas about how to do it

 

[Gayan Soyza]

Try this circuit but its for a small motor.

A & B are the logic levels.There are tons of Hbridge circuits in the net.

**broken link removed**

 

[things]

haha, i like that animation

 

[Inferno]

10x guys for your help... but i think that the animation circuit can t run a 12 volts 0.5 A motor.. right ?

 

[things]

could you use relays?

 

[Gayan Soyza]

10x guys for your help... but i think that the animation circuit can t run a 12 volts 0.5 A motor.. right ?

You can connect but you wont get the full RPM also starting Torque will be high.See whether transistors getting hot immediately if so have to shift to another high current design.

 

[Nigel Goodwin]

Well the initial question bears no resemblance to the actual requirement, but to reverse the motor a simple DPDT relay driven from a 555 timer is really all that's required.

 

[Inferno]

ok guys... i think the l298 and the 555 timer could be an easy solution...!
but the problem is that this is the first time i work with a 555 timer... how can i get the 2 hz frequency ??? and what is the most common 555 timer IC ??
and about the l298 what are the EnA and the EnB pins for ??

 

[things]

i think it depends on the resistance between two of the pins?

 

[Inferno]

hmmmm thinking abt the dpdt relays and 555 timer...
the 555 timer should work on 5 volts or it could work on 12 volts ??
anyway ... what would u recommend for a dpdt relay that work with the 555 timer and 12 volts dc motor ?

 

[Inferno]

and could a relay handle switching 2 times every second.... ??? ( 2 hz frequency )

 

[Nigel Goodwin]

and could a relay handle switching 2 times every second.... ??? ( 2 hz frequency )

Yes it can - but can the motor handle it?, and why do you want to do this anyway?.