help with circuit design

[kitchensink]

Hi,
I am new to this but reading a lot. My son wants to build an Electrolysis project for this school. He wanted some help on this. I am looking for a timer that reverses polarity after a few seconds for a set voltage. So here is an example:

1. +10 volts for 3 seconds
2. - 10 volts for 5 seconds

what to use a relay since I dont know what current it is going to draw.

He wants to be able to adjust the voltage and the time for his experiment. the max voltage is 12 volts. So are there any circuit designs out there

Thanks

 

[KrisBlueNZ]

Hi and welcome to the forums

Yes, you can do that. It's not difficult. You can use the ubiquitous NE555 (just called the "555") to control the relay(s).

Does this reversing voltage need to be a "one-shot", i.e. a single sequence triggered by a pushbutton, or a continuously repeating sequence?

How are you planning on varying the voltage? Your control circuit will need a fairly constant voltage, probably 12V is a good choice. This will need to be a separate power supply if you're varying the voltage you send to the electrolysis circuit.

What country are you in? (There's a place for this information in your profile.) Do you have a preferred supplier for electronic components? I often recommend Digikey in the U.S. if you're over there, but I can give you part numbers for Radio Shack parts, or parts from any other supplier, if that's easier for you. Most electronic component suppliers have the 555 and suitable relays.

 

[CDRIVE]

This circuit can be easily modified to fulfill your requirements.

Chris