# Apply voltage for X seconds

Discussion in 'Electronic Basics' started by [email protected], Apr 24, 2007.

1. ### Guest

Does anyone know of a quick way to make a circuit closed for a certain
period of time after it receives a signal? It's been too long since
I've messed with most circuit components and I can't remember enough
specifics.

2. ### Homer J SimpsonGuest

Minimum and maximum time range?

3. ### John FieldsGuest

---
More than likely, a monostable multivibrator (AKA one-shot)

http://datasheets.maxim-ic.com/en/ds/ICM7555-ICM7556.pdf

What do you mean by "closed", how long a time, how much current will
the circuit need, and what will the signal to start the timer look
like?

4. ### Anthony FremontGuest

You need to furthre explain what you mean by "certain period of time",
seconds/minutes/hours/days? What do you want to happen if the "trigger"
event occurs again during the timing cycle? Should it be ignored or should
it restart the timing cycle? Perhaps a NE555 timer, 74hc123, 74hc221 or a
PIC depending.

5. ### JamieGuest

You need a One shot timer..
Look on the net for 555 timer examples.
I assume you need it to only close once and
release to not close again until you remove the
signal and recycle it?

7. ### Walt FlesGuest

maybe feed the multivibrator into something like a 4106 bilateral
switch?

10. ### Walt FlesGuest

Then the bilateral switch can complete a circuit and apply how much
voltage you need to.
Depending on what type of circuit needs the voltage and/or how much
voltage you may end
up using a diac or triac or scr.

11. ### Michael A. TerrellGuest

Have you ever actually USED a bilateral switch? They are low leve,
high impedance devices. They are not intnded to switch any current. The
on resistance is high, and the part number was 4016, not 4106. Also,
the 4016, and its sucessor, the 4066 are QUAD BILATERAL SWITCHES. Early
CMOS devices lock up if the voltage is outside the secified range, or
just quit working

--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

12. ### Walt FlesGuest

Ive used them with op amps as a semiconductor replacement for an atari
joystick that worked quite well,
with a potentiometer joysticks hooked to them. That was when Radio
Shack sold such stuff.

13. ### Michael A. TerrellGuest

That is a completely different application. You were working with
low signal levels, and high impedance circuits.

--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida