This shadow detector circuit operates using two LDRs and effectively detects the difference between the light levels and triggers a loud audible warning siren. In circuits which uses a single LDR (photoresist), the detection may not be as sharp as with two LDRs discussed here.Operational details of the shadow detector circuit may be studied as […]
Archives for 2015
Lathe Machine Over Load Protector Circuit
In this article I have explained a simple overload cut off circuit for safeguarding heavy mains operated machines such as a lathe machine. The idea was requested by Mr. Howard Dean. Technical Specifications May I first say I have very little knowledge of electronics although I could follow a simple diagram. I operate a small […]
Simple Ultrasonic Sound Sensor Alarm Circuit using Opamp
This article discusses a simple ultrasonic sound sensor alarm circuit which may be appropriately set for detecting sound pressures well above the normal human listening capacity, that may range from 20 kHz and over. Ultrasonic Concept Ultrasound or ultrasonic sound waves was probably invented even before humans existed on this planet by a few of […]
Simple RGB LED Color Mixer Circuit using LM317 IC
In this post I have explained a simple LM317 IC based RGB 3 watt LED color mixer circuit, which can be used for demonstrating the color mixing effects of red, blue, green colors as specified in the standard color charts. The idea was requested by Mr.Praveen. Technical Specifications My name is Pravin, I work in […]
Simple Pneumatic Timer Circuit
In this article I have explained a simple two step IC 555 timer circuit which can be used for sequentially operating any specified industrial mechanism system, in this application it’s used for operating a pressurized pneumatic ball throwing arm. The idea was requested by Mr. Ray Strong. Technical Specifications So glad I found this site, […]
Transformerless Voltage Stabilizer Circuit
In this post I have explained a simple circuit design which ensures a perfectly stabilized 220 V or 120 V mains voltage across the connected load, without using relays or transformers, rather by the use of accurately dimensioned and self adjusting PWM pulses. The idea was requested by Mr. Mathew. Warning: Circuits I have explained […]





