using transistors to latch

[harps]

hello : )

Is it possible to use a few transistors to latch a 5v signal, for example: if 5v is input for a short period..the little circuit gives 5v out forever? i am using a 555 timer at present to hold a 5v signal but the circuit takes up lots of room as does a mechanical relay. so thought a few transistors in a particular fashion would work?

thanks for your help. : )

 

[Nigel Goodwin]

A bistable multivibrator is one way, takes two transistors, and is (was) the basic building block of digital computers.

 

[MrAl]

Hi,


Build two transistor inverters and then cross connect them. Use one input as the input.

 

[harps]

thanks

i found this bistable multivibrator

Bistable Multivibrator (Flip-Flop)

it works very well . ( once i put my transistors the right way around)

thanks very much guys : )

 

[carmusic]

Or just use a SCR, on dc once it is trigerred it stays on forever