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 […]
Newly Updated Circuit Projects:
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 Programmable Timer Circuit
This programmable timer can be used for switching a load ON and OFF with two sets of time delays, which are programmable from 2 seconds to 24 hours independently. The delay timings are adjustable according to the users personal specs. The ON time delay and the OFF time delay are independently settable and this facility […]
Simple Delay Timer Circuits Explained
In this post I have explained the making of simple delay timers using very ordinary components like transistors, capacitors and diodes. All these circuits will produce delay ON or delay OFF time intervals at the output for a predetermined period, from a few seconds to many minutes. All the designs are fully adjustable. Importance of […]
Simple Voltage-to-Current and Current-to-Voltage Techniques – By James H. Reinholm
There are many types of voltage-to-current and current-to-voltage converter circuits, and most of them use a combination of opamps and transistors to achieve a high level of accuracy. But when high accuracy isn’t necessary, a simple converter of this type can be made using just one or two resistors. Resistor as Voltage to Current Converter […]





