Use this kit in A-STABLE (continuous train of pulses) or in the MONO - STABLE mode (triggered time delay). This kit will time circuits from nano-seconds to 30 minutes. Comes with a variety of resistors and capacitors suitable for most applications. Included in the ET-1 kit is a mathematical formula to determining the time segments. This kit delivers 100mA of output. If you need more power you must use a relay large enough to handle your needs. We have larger power kits available, the Triac kit TP-1 or the Relay kit RP-1. We also have a new kit PRC-1, this is a relay kit that gives programmable functions. All three kits have a 3amp output. All three kits are listed here. If you are not good at math we suggest that you buy the kit ETC-2. The ETC-2 kit comes with all the same parts and will give you the same functions but in addition it is supplied with a computer disk which calculated the proper time you are looking for. Operating voltage 4.5 to 12V DC. SIZE: .9" x 1"