My Light Diagram

The simple indicator presented in this article may be combined, in principle, with any circuit that contains an LED bar display driven by a Type LM3914 IC. It ensures that an LED will light when all LEDs driven by the LM3914 are out. This prevents one drawing the erroneous conclusion that, since all the LEDs are out, the circuit is switched off. The circuit then continues to draw current, which, especially if it is battery powered, costs unnecessary money, apart from other considerations. The LED in the monitor draws a current of only 1 mA. When the LEDs forming the bar, D1–D10 are all out, there is no potential difference across R3, so that T1 is off and T2 is on. Circuit diagram LED Bar Off Indicator Circuit Diagram This results in T3, in conjunction with R5 and the internal reference voltage of IC1, to form a current source that causes a constant current to flow through D11 so that the diode lights. When on of diodes D1–D10 lights, a potential difference ensues across R3, which caus...

Build a 10 LED Bar Dot VU meter circuit based LM3915 . It differs in many respects from other applications on the same chip. The circuit is intended for those who want a VU meter that is connected directly to the output of an power amplifier.  10 LED Bar Dot VU Meter Circuit based LM3915 Circuit Diagram It’s possible to adjust the sensitivity to work with amplifiers that have different output power, you just need to change the value of R1 according to Table 1. In case you did’n find the exact resistor value, then choose the next standard value (for example if you cannot find 33K ohm, then find the 36K ohm), or if you want maximum accuracy you need to put resistors in series or in parallel to achieve the correct value.   You can use various types of LEDs (round or square) to get the visual and aesthetic result you want. The switch S1 will allow you to choose whether VU meter will work as a bar or one by one (dot). In position ON [closed switch], the LED operation is Bar, while ...