This is actually two separate circuit plans - #1 - a timer which triggers a relay, and #2 - the relay controlled ignition circuit. After looking at the schematic, you may wonder what the point of the relay circuit is - why not just put the igniter in place of the relay coil on circuit one? The answer is this: There is not enough current to burn the steel wool, due most likely to the resistance of the 555 ti ...Read more ›
Electronic 555 Timers Circuits
Electronic 555 timers circuits are utilized in many applications. From appliances and alarms to sprinklers and lights, our lives are completely intertwined with digital timers. In makeshift circumstances, an electronic timer is an invaluable tool for automating tasks. The most common use in wartime is allowing a fighter time to escape from the scene where an explosive device may be planted – and initiated after a set amount of time.
The following documents detail how timers can be built out of gadgets and components ‘lying around’.
The most obvious is by simply using an analog clock, with tinfoil, insulated on the inside, wrapped around the hour hand or the minute hand, depending on the amount of time required. A peg is soldered onto the clock face (or attached by some other means) with tinfoil on it. When the hand touches the peg the tinfoil completes the circuit – initiating whatever you choose.
This archive presents plans and diagrams for making electronic timer circuits, such as; 555 timer circuits.