Telephone status indicator with LED
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...
Category: LED-Circuits
Button and four LED Lights
Need a design – Simple one button push button to turn on 4 different LED (3mm Dome) every time you press the button. 555 Circuits, LED Schematic. User Interface Design. JE USA Attached is...
Electronic Fifteen LED Roulette
The following was submitted on July 11th, 2007. Message: I want to combine Ne555 with 74154 IC.The indication of the outputs must be shown with LED’s but up to so far it need 15...
Running Lights with CD4017
The 555 Astable generates a clock for this circuit, an oscillator giving a square wave output at pin 3 which is counted by 4017 to give a running lights effect. Digital Timers Counters and...
Millivolt Meter using a LM3914 LED Dot Display
Here is a easy to read ‘Analog’ Millivoltmeter. Just like the Moving Coil Voltmeter, but does not have that resolution. This gives a easy indication of process progress or parameter magnitude from a large...
Resistance Measurement Analog LED Meter
This is a LED Analog Meter, This can be used as a Resistance Meter and Low Impedance Voltmeter for Battery Levels. To measure battery voltage, the R5-R12-R17 etc. part of the Reference Resistor Divider...
LM555 Voltage Doubler
This circuit shows the voltage doubler working with a 555. LM555 has good drive 200mA, both Vcc and Gnd. 555 has the advantage of having a high drive as well as being a Mixed...
FET Current Source and MOSFET
This is a constant current source using a FET. This is the most simple replacement to series resistor to limit current. The N-Channel FET BF256C can give 15mA current. Simple Methods Before you get...
