Constant Current Source LED Drive
This is a Constant Current Source LED Driver, When the LED driver Upper-NPN is driven by a voltage thru 4.7K the LED lights up. Assume that the Lower-NPN at bottom is absent. The current...
This is a Constant Current Source LED Driver, When the LED driver Upper-NPN is driven by a voltage thru 4.7K the LED lights up. Assume that the Lower-NPN at bottom is absent. The current...
This will monitor telephone status without loading the telephone line, this way if you have two phones in parallel you will know if one of them is busy. Connect the two ends of circuit...
This LED Indicator uses a LM339, a quad comparator. LM339 can work on single or dual supplies, it has a open collector output that can drive 15mA, low power consumption. The circuit is an...
This Circuit helps in the monitoring of mains supply voltage. It does not use a isolation step down transformer. This has to be constructed only by skilled people with knowledge of safety requirements. C1...
This circuit is used to detect objects by reflected infrared light. It can be built into a cylindrical enclosure just like an inductive proximity switch. Part of – InfraRed Detector for Proximity Switch This...
This circuit is derived from a Siemens Application Note 1974. This circuit uses common components of today. The circuit is here as it is of high educational value. I have not tested it. You...
This article will explain the way a simple transistor based current source is designed, this will give an idea on how some components can be used in a practical way to make the circuit...
This is a mains 230V AC voltage indicator and is a LIVE CIRCUIT, so take care. The Resistor has to be a fusible ceramic wire wound and the capacitor 630V AC or higher capacity....