# Simple Voltage Indicator by LED and Zener diode

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In electronic instrumentation is needed.One friend of mine, once said that a good tool. Not need to be expensive.
It is important to use enough. Today I will try to collect circuits Simple Voltage Indicator. by LED and Zener diode
You look into the concept. Although is small circuits. But it might make circuits great work was complete.

## 1.Visual zero beat indicator

This circuit is suitable for an indicator to audio signal lower than 3Vp-p. In the circuit, we use a very small parts with only two of the LED display and built-up resistor for current depression.
Light-emitting diodes(LED) connected with reverse polarity provide a visual indication of zero-beat frequency.
Each Led is on for only half a cycle of the input.
When the input frequency is more than 1 kilohertz away from the zero-beat frequency, both LEDs appear to be on all the time.
As the input frequency comes within about 20 hertz of zero beat, the LEDs will flicker until zero beat is reached.
Both LEDs glow or flicker until zero beat is reached, when they go out.

## Small three step level indicator

Today we look at the concept of a level indicator circuit which was built to be very small, can be displayed with LED 3 step. When see in the circuit is very simple. We use a variable resistor(Potentiometer) with 3 unit only, making this the circuit cheap and easy.

The Resistor values of Potentiometer VR1-3 are determined by the type of LED, when we used MV 50 LEDs so resistant by steps of 2K for the 2V and drain current (series circuits) in all three LED lights on the 5mA. Chain can be extended. But the rapid increase in the drain current and the first LED in the current supply.

## Very Simple Voltage Level Indicator

Today we come to see Voltage Level Indicator in model easy most. It is use easy part electronics only. The Zener Diode, Resistor , and , LED as a result can show already. By in each the circuit LED stick bright when V+ go up arrive at Breakdown voltage. And Vz of Zener diode +VLed should use RS for LED one by one. The circuit on the right will testify read the value is Bar Graph. When Zener Diode quietly enhance the value Vz . This circuit may is is simple good may advantage for friends , please sir.