-2
\$\begingroup\$

I have a 9V 555 timer circuit and I want to use it to automatically turn on and off a 220V water pump. What can I use to connect the timer and the pump? Is there like a transformer or something?

\$\endgroup\$
2
  • 4
    \$\begingroup\$ How often? Current rating of the pump? More details needed... \$\endgroup\$
    – Matt Young
    Feb 25, 2014 at 0:51
  • \$\begingroup\$ I already have the timer set. All I need is a relay but thanks for asking anyways \$\endgroup\$
    – LorenzKyle
    Feb 25, 2014 at 1:19

2 Answers 2

0
\$\begingroup\$

All you need is a relay

Here you have got one that can be set on and off with 5V: ebay

\$\endgroup\$
2
  • \$\begingroup\$ That is a guess at best. \$\endgroup\$
    – Matt Young
    Feb 25, 2014 at 0:55
  • \$\begingroup\$ that is one answer \$\endgroup\$
    – kimliv
    Feb 25, 2014 at 0:58
2
\$\begingroup\$

A 555 doesn't keep any meaningful time. If accuracy is important, and you want some more complex logic than toggling on and off every x seconds, then I'd recommend a Real-Time-Clock (such as the DS3231, which has alarm features) that's connected to a basic microcontroller like a PIC12F. Component tolerances for really long periods may be an issue; I'm guessing the pump won't be toggled very often.

From there, you need to use the output to switch mains. Using your own homebrew circuits to switch mains is a potentially deadly endeavor if you are not completely confident in what you are doing. Stop now if you aren't and buy something like this instead. Otherwise, solid state relays are readily available to switch high voltage mains from low voltage DC sources like a microcontroller and provide isolation. This one from Sharp does up to 8A at 400VAC. You need to find one that fits your specifications.

\$\endgroup\$
1
  • 3
    \$\begingroup\$ Q:555;A:PIC ... Olin, is that you? :-) \$\endgroup\$ Feb 25, 2014 at 10:47

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.