1. Home
  2. Electronics Design
  3. Need a bit of help with a vcr circuit

Need a bit of help with a vcr circuit

I have to make a circuit that simulates how a vcr works.

Right now play, stop and forward work.

But, I dont know how to do the following

If play is on and then forward is pressed, both lights work.

If forward is on and then play is pressed, play lights up and forward turns off.

If the above two work, they should also be able to be shut using the stop button.

Btw, the forward light blinks which is why the clock is connected to the and gate.

Any help will be appreciated as Ive been trying to get it to work for the past few hours

thx

this is what I have so far

formatting link

Reply to
mirza1867
Loading thread data ...

So, what you are asking for is for "forward" to go off if "play" OR "Stop" is pressed. Is that right? I don't see the problem.

--
--
kensmith@rahul.net   forging knowledge
Reply to
Ken Smith

yeah, that works right now

but if forward is on and play is off. then if i press play, forward should stop and play should stay on

Reply to
mirza1867

Ken gave you the clue: if play OR stop is pressed then forward should go off. So you need an or gate to the S pin of the forward flipflop and both stop and play should be an input of that or gate.

BTW, why did you choose to use inverted logic? Nothing wrong with that, but most people would use the R(eset) for the stop function instead of the S(et).

--DF

Reply to
Deefoo

schreef in bericht news: snipped-for-privacy@v46g2000cwv.googlegroups.com...

First of all, I would use the play/ff buttons to SET the flipflops, the stop button to RESET the flipflop, and connect the lights to the Q outputs instead. Makes it a bit easier to understand, compared to the reversed logic you are using now. Do that first.

The forward FF should be reset when STOP is pressed, OR when PLAY is pressed. Note the OR in this description. So you need to put in an OR gate somewhere.

--
Thanks, Frank.
(remove \'q\' and \'.invalid\' when replying by email)
Reply to
Frank Bemelman

Deefoo wrote: (snip)

There's no accounting for taste. Back in college days, Logic Design prof. took off points for my solutions to final exam questions that involved loop equations. My transgression was assigning negative values to voltage drops in the direction of current flow and positive values in the opposite cases (which I had also done in every homework problem, all semester). The "It's not wrong but most people do it differently" excuse didn't hold then either. After some discussion, I got my points back. :-)

--
Michael
Reply to
Michael

--- View in Courier

. Vcc Vcc . | | . RUN [R] [R] . ____ | | +_----+ RUN . +--O O---+---------------|----+----|S Q|--[R]--[LED>]--GND . | ____ | | |_ _| . +--O O---|---+-[]--GND . | STOP | | |A +-----+ STOP . | [CR][CR] [CR] . | |A |A | . | | | | . | | | | . | | | | Vcc Vcc . | | | | | | . | | | | [R] [R] . | ____ | | | | | +_----+ FF . +--O O---|---|--------+--|----+----|S Q|--[R]--[LED>]--GND . | FF | | | |_ _| . | +---+-----------+---------|R Q| .GND +-----+ .

-- John Fields Professional Circuit Designer

Reply to
John Fields

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.