Hey guys, I'm working on a simple circuit. Here's the gist of it: I want to hook up a 4017 IC (used in chaser-circuits) and upon each output going HIGH, I want to activate a relay and pass 12V from a low-grade car-battery through it. The circuit itself is easy; I've made chasers using the 4017 IC before and am well-versed in relays. My problem is that I'm pretty sure the 4017 doesn't have the power to switch an relays. (perhaps a solid-state relay would work?). But I was wondering if anyone had any tip for this. Perhaps some type of driver or bi-lateral switch that would control a very large output from a very small input. From looking at the datasheet, the 4017 outputs a voltage near the supply voltage, but only about 4mA of current. So that's the situation. Any tips would be appreciated. Thanks. -Joe

 

Just a plain transistor design between the 4017 and a relay is all you need.

 

Transistors and inductive kickback diodes but depending on you relay's coil current draw requirement possibly the ULN2804A.

creakndale

 

Thats about it.

You could use a relay with a 5v coil, and a transistor or 2 (DARLINGTON PAIR) from the 4017 to the relay coil.

 

Good old DS2003 darlington driver chip. Very easily drives relays.

 

The DS2003 is a National Semiconductor specific part number for the industry standard ULN2003 7-channel Darlington driver array.

 

thanks guys! -Joe