Doorbell-Controlled Porchlight

This add-on circuit automatically turns on your porchlight when your doorbell rings, so you can see the person ringing the doorbell at the doorstep. This also helps to guard against burglars,...

Intercom with Musical Ringtone

Here’s a low-cost two-way intercom circuit with musical ringtone that can be made using readily available components (see Fig. 1). Melody generator IC UM66 (IC1) generates ringtone for the intercom circuit. The...

Ultra-Bright LED Lamp

This ultra-bright white LED lamp works on 230V AC with minimal power consumption. It can be used to illuminate VU meters, SWR meters, etc. Ultra-bright LEDs available in the market cost...

Mains Manager

Very often we forget to switch off the peripherals like monitor, scanner, and printer while switching off our PC. The problem is that there are separate power switches to turn the...

Solidstate Switch For DC-Operated Gadgets

This solid state DC switch can be assembled using just three transistors and some passive components. It can be used to switch on one gadget while switching off the second gadget...
circuit ebooks

10 Free eBooks On Circuits

From understanding basic circuits to creating complex circuits, from analog to digital circuits, from designing circuits on PCs to circuits analysis, these free ebooks on electronics carries everything that you ever...

Versatile CMOS/ TTL Logic and Clock Probe

For fault diagnosis of any logic circuit, you need a probe that can test the logic level or existence of clock activity. The circuit shown here can be used to test...

Electronic Scoring Game

You can play this game alone or with your friends. The circuit comprises a timer IC, two decade counters and a display driver along with a 7-segment display. The game is simple....

Telephone Line Based Audio Muting and Light-on Circuit

Very often when enjoying music or watching TV at high audio level, we may not be able to hear a telephone ring and thus miss an important incoming phone call. To...

Low-Cost PCO Billing Meter

The circuit presented here can be used in PCOs for displaying the actual bill. The comparative disadvantages of the presented circuit are as follows: 1. The calculator used along with this circuit...