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)...
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....
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...
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...
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...
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...
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...
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...
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....
40-Metre Direct Conversation Receiver
Using the circuit of direct-conversion receiver described here, one can listen to amateur radio QSO signals in CW as well as in SSB mode...
