A very simple but highly efficient combination lock circuit is shown in the figure. Any type of on/off switches can be used, varying from commercially available inexpensive types to more sophisticated ...

It’s late at night. The solder smoke keeps getting in your tired eyes, but your project is nearly done. The main circuit is powered by your 13.8 V bench supply, but part of the circuit needs 9 V. You ...

Low-power circuits commonly use transformerless power supplies. However, the use of earth grounds in many of these circuits creates a serious problem that is often ignored. The very popular Microchip ...

In designing and prototyping electronic circuit boards there is no quick or simple way to produce results. Many hours of design and development need to be expended on prototype layouts along with ...

This simple electronic bicycle horn circuit uses only one gate of a 4093 quad 2-input NAND Schmitt trigger, U1, conected in a simple, low frequency, square-wave oscillator circuit. The oscillator’s ...

This simple code lock circuit described here is of an electronic combination lock for daily use. It responds only to the roght sequence of four digits that are keyed in remotely. If a wrong key is ...