Detect Food Spoilage with Sensors
Foodborne diseases, commonly known as food poisoning, are a very common occurrence. According to the Centre for Disease Control and Prevention (CDC), roughly 48...
Low-Cost Hearing Aid Using IC 741
This low cost hearing aid circuit offers the advantages of high sensitivity, low current consumption and light weight.
Audio signals are sensed by the condenser...
TV Pattern Generator
This single-IC TV pattern generator is useful for fault finding in TV sets. You can correct the alignment of the timing circuits of the...
Mains Interruption Counter with Indicator
This mains interruption counter circuit counts mains supply interruptions (up to 9) and shows the number on a 7-segment display. It is highly useful...
Resistance Measurement Using Sample and Hold Method
A sample and hold circuit, as the name implies, samples an analogue input signal and holds its value until the input is again sampled....
Digital Thermometer
This digital thermometer can measure temperatures up to 150C with an accuracy of +_1C. The temperature is read on a 1V full scale-deflection (FSD)...
Solidstate Signal Lamp
This solidstate signal lamp is a good alternative to revolving mechanical signaling lamps used in ambulances. It uses ultra-bright blue LEDs for signaling. However,...
PC Driven LED Display
Here is a PC driven LED display circuit to generate sequentially running light effects using a simple program written in C. The output of...
Parallel Telephone with Secrecy and Call Prevention
This parallel telephone circuit provides secrecy when two or more telephones are connected in parallel to a telephone line. The circuit also prevents incoming...
False Triggering Eliminator for Timer 555
Normally, false triggering of timer IC 555 takes place during power on, resulting in unwanted output, which starts the timer’s time cycle. The circuit...
