I am presenting a circuit design here in response to a request sent by one of the avid readers of this blog. The proposed circuit is of a sequential LED light driver, especially designed to suit the application of a multipurpose car tail light indicator. Circuit Connections The circuit is integrated to the brake switch […]
Archives for 2012
4 Simple Uninterruptible Power Supply (UPS) Circuits Explored
In this post I have investigated 4 simple 220V Mains Uninterruptible power supply (UPS) designs using 12V battery, which can be understood and constructed by any new enthusiast. These circuits can be used for operating an appropriately selected appliance or load, let’s explore the circuits. Design#1: Simple UPS using a Single IC A simple idea […]
Automatic Inverter Output Voltage Correction Circuit
The common problem with many low cost inverters is their incapability of adjusting the output voltage with respect to the load conditions. With such inverters the output voltage tends to increase with lower loads and falls with increasing loads. The circuit ideas explained here can be added to any ordinary inverter for compensating and regulating […]
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 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 Transistors
If you have understood correctly, how to use transistors in circuits, you might have already conquered half of electronics and its principles. In this post we make an effort in this direction. Introduction Transistors are 3 terminal semiconductor devices which is able to conduct relatively high power across their two terminals, in response to a […]





