automatic soldering iron switch

M.A. Prins automatic soldertn iron switc VVe all know that it is quite easy to forget to turn off the soldering iron. If you then go out of the house with other things on your mind, it is just possible to return to find a heap of smoking rubble. This would be extremely upsetting, especially when this sort of calamity can easily be avoided. The results are not usually so dramatic, but the least you can expect is a bigger electricity bill. The circuit here will iron the problem out and will repay the effort of making it in a very short time. The circuit operates as follows. IC1 is an oscillator which generates a time interval of divided by 213 of an hour. At the end of this time about a quarter and a buzzer sounds. Unless S1 is a LED flashes pressed within 50 seconds, the circuit switches itself, and the soldering iron, off. If Si is pressed, IC1 re-starts the 15 minute period. satisfac- Although the prototype circuit behavedthe mains N1 ... N4 = IC2 = 4093 I L-- 7BLXX 7 switch on. ...