1Hz Clock Generator Circuit Using COB

Let's familiarize with a COB - chip on board device by building a precision 1Hz clock generator. Circuits that usually generate 1Hz clock makes use of ICs with variable capacitors but they are not very precise. ( micro controller based one should be precise but it costs large ). better accuracy can be obtained by a COB found inside a digital clock, which is cheaply available in the market.

Simple Laptop Audio Amplifier Circuit

When it comes to laptop sounding, most of the laptops currently in the market has very low sound output (laptops like DELL XPS is an exception). If you need more powerful sound, you need to amplify the sound output from the laptop. Here's a simple amplifier circuit making use of the SANYO LA4440 IC which is ideal for low power audio applications because it gives better sound clarity and less distortion.

Laptop audio amplifier circuit

Fortunately the circuit diagram is very simple and even a beginner can assemble and debug it. The circuit is built around the previously mentioned LA444o IC and a few components. The amplifier is a dual channel one with 6W for each channel. So a 10 W speaker would be very sufficient. Connect pins 2, 6 and ground of IC1 to the stereo jack which is to be used with the laptop.

LED Running Display Using NE555

Here's a circuit to build a led based running display using easily available general purpose timer IC NE555 and a popular decade counter IC CD4017. This display consist of 24 LED's of four layers. The NE555 is wired as an astable multivibrator whose output triggers CD4017 counter.