Four Station Quiz
Here we have another Quiz circuit using a number of CMOS ICs. Now the number of contestants can be easily increased even though the present circuit shows only four. It uses a two input Quad AND gate (74HCT08), a four input Dual AND gate (74HCT21), a dual D flip flop (CD4013), and a 555. Truth [...]
Light Alarm (Sun Up Alarm)
This circuit designed to sound a loud alarm at the break of the dawn especially for those wh cannot wake up even with an alarm clock. Circuit can be modified as an intruder alarm or as a security alarm. Needless to say that 1.8 KHz astable multivibrator with 555 is used here again with a [...]
Basic Oscillator (Tone Generator) At 1.8 KHz -alarm circuits
Here we have an astable oscillator built around 555, which gives an alarm tone of 1.8 KHz directly driving a speaker. This is basic alarm circuit, which is later used in many other projects in the book. While the circuit shows only 1.8 KHz operation, it can be adapted to different applications by changing frequency [...]
IC555 Interal diagram and description
IC 555 has been one of the most popular ICs since Signetics introduced it in the early 70s. 555 is also called as a TIMER IC. This 8-pin chip is a versatile device suitable for astable, mono-stable and bi-stable operations. It is such a multipurpose device that hobbyists find clever uses of it everyday. It [...]
