My Circuit

When you want to mount components on a PCB or a piece of prototyping board, you not only want to do this quickly, but also tidily. The bending of really tidy wire links with the correct pitch is often a tedious chore. The following is a handy aid for doing this. Using a small piece of 0.1 inch (2.54 mm) prototyping board, you can very easily make a handy bending jig for wire links. With a jigsaw, cut the piece of prototyping board into a staircase shape as shown in the drawing. You can make it as big as you need. Make sure that the horizontal cuts are slightly  towards  the outside with respect to the holes, so that clear indentations remain in the horizontal sections. Bending a wire link is now very easy: choose the desired pitch on the jig (dashed line), take a piece of wire and fold it sharply around the indentations corresponding to the selected  pitch. A neat wire  link  is the result, with exactly the right pitch and ready for soldering tightly into the PCB or prototyping boa...

Here is a simple circuit of wire-break alarm that activates after a delay of 15 to 30 seconds. When the thin-wire loop running across the entrance door is broken, the alarm sounds after a delay of 15 to 30 seconds, the time period set through VR1. Thus the occupants get sufficient time to lock the room from the outside and catch the thief.  The circuit uses CD4060, which is a 14-stage ripple-carry binary counter/divider and oscillator. It is wired as a timer here and does not need input pulse for trigger. CD4060 gets activated as soon as the power supply is switched on. Output O13 of CD4060 goes high after the lapse of preset delay set through VR1. Transistor SL100 (T2) is wired as a switch to power the timer section built around CD4060. When the wire loop is closed, transistor T2 does not conduct. So power to the timer circuit is not available and the piezobuzzer does not sound.  Wire-Break Alarm With Delay Circuit Schematic On the other hand, when the wire loop is broken by ...