The digital time clock explained here is a circuit which most electronic amateurs would love to make. You might have heard about digital clocks made from clock ICs such as the popular LM8361, MM5387 etc but these ICs could be today quite obsolete and/or complex to build. Circuit Operation The present design is much easier […]
Sensors and Detectors
How to Make LED/LDR Opto Coupler
Ever needed an application where the resistance of a resistor needed to vary proportionately in response to a PWM or a varying analog voltage? Yes, this is where an LED-LDR opto-coupler becomes so useful. The following image shows the symbol for a LED LDR opto-coupler. Any other regular opto-coupler, such as an LED/transistor, LED/FET, or […]
Simple Peak Detector Circuit to Detect and Hold Peak Voltage Levels
In this article I have explained about a peak detector circuit, its working principle and how to implement it in clap operated circuits for illuminating an LED in response to clap sounds. What is Peak Detector A peak detector is a circuit which holds maximum amplitude value of a signal. If a signal varies rapidly […]
How to Use TTP223 Capacitive Touch Switch Module [Pinouts Explained]
In this article I have explained how to connect and use the TTP223 capacitive touch switch module. These modules work using 2.5V to 5V. They are all pre-debounced, all you need is to provide the DC supply across the VC and GND terminals, and you get an output in the middle. So it is really […]
Simple LDR Motion Detector Alarm Circuit
Here I have explained how to build a simple LDR based motion detector sensor circuit using ordinary parts such as LDRs and opamps, reasonably accurately. What are Motion Detectors Motion detector or sensor alarm is a device which detects the presence of a motion or movement within a certain fixed range and raises an alarm […]
How to Use Diodes, Transistors, ICs as Temperature Sensors
Normally we find thermistors being used as the sensor for detecting and monitoring temperatures in electronic circuits. However, ordinary semiconductor components like transistors and diodes actually work better than thermitors when it comes to detecting temperature changes. In fact, this feature happens to be one of the greatest drawbacks of semiconductor devices, whose working characteristics […]