Can You Create a Circuit That Automatically Shorts 2 Cables Every Second?

[roboticmehdi]

hi everybody. i need a circuit which will short 2 cables for 0.5 seconds every second. let me explain like this:

_______________
(+2.4v) | | (0)
-----------| |--------------
| |
-----------------

in the ugly drawing above you can see two wires with a potential difference of 2.4 volts connected to a box. the box just represents the circuit that i want to make with your help.
this box must have zero resistance for 0.5 seconds and infinity resistance for 0.5 seconds. so its like a pulsating current with 1Hz across this two wires. Can you guys help me with this ? i have circuit elements like resistor, capacitor, leds, transistors(only BDX53C, BD243C, TIP41C and BDX54C), and etc... The timing doesn't have to be so strict, 0.5s+-0.05 is fine. The current that will be drawn during shorting is not high, not higher than 100ma. I need the simplest and most efficient circuit that you know :)

 

[roboticmehdi]

sorry about that drawing, it didnt come out like i wanted. here is correction:


2.4v ----------------|BOX|--------------- 0

 

[Bassalisk]

Simplest?

Put BD243C npn transistor across those cables(collector to 2.4V side). Use a 555 timer for sending square wave pulses to base.

http://pokit.org/get/img/107e57d75a27c44c658941c60d53b2b7.jpg

Here are the values for 555 timer.

 

[mdjensen22]

You could always drive a little reed or telecom relay if desired. Those are pretty quick and will give as close to a dead-short as you can get.
The 555 timer circuit above should be able to drive one of those without issue.

 

[darkwood]

If you suspect you may need to alter timings etc and don't mind spending a few extra pounds you con get a simple logic controller with relay outputs, a basic logic programme will give you an unlimited output function with easy alterations and time scaling down to the thousands of a second.
You can get a starter kit and i promise you, you'll have programmed it within the hour even with no experience, the best thing is you can save the programme and load a new one for your next project.