Switch Problem

[cljunior]

Hi guys

I thought i'd solved this problem before, but i found out that my old method is not viable anymore, because we are not allowed to use relays in our project.

I am trying to implement a digital switch (like a switch on a hifi that gets turned on/off into standby via a remote, or via the on/off button).

I was going to use a D flip flop after my receiver, then a BJT, followed by a relay.

Two problems.

1) How do i get my D flip flop to hold the value that i want (ie. on or off)?
2) What can i use in place of a relay?

Any help is greatly appreciated.

Cheers
cljunior

 

[nettron1000]

1) How do i get my D flip flop to hold the value that i want (ie. on or off)?

Im not sure what you mean exactly, but a flip-flop will hold its output automatically when the pushbutton is released. Its like a one bit memory.

2) What can i use in place of a relay?

You can get solid state relays but they can be quite expensive. You can also use a transistor switch but you need to know how much current your load is drawing.