Components Requirement

$1.$ Humidity sensor $($or any input signal representing humidity levels$).$

$2.3$ LEDs $($different colors for better clarity: e$.$g$.,$ green, yellow, red$).$

$3.3$ transistors $($NPN or PNP$,$ e$.$g$.,$ BC$547$ for NPN$).$

$4.$ Resistors $($for LEDs and transistor bases$).$

$5.$ Capacitors $($optional$,$ for noise filtering$).$

$6.$ Wires and breadboard.

Circuit Design

Step $1$: Divide Humidity Levels into Voltage Ranges

Use the humidity sensor output, which gives a voltage proportional to humidity.

Assume:

Low humidity: $0$V$1$V$.$

Medium humidity: $1$V$2$V$.$

High humidity: $2$V and above.

Step $2$: Voltage Dividers for LED Activation

Create thresholds using resistors to divide the voltage for the three levels:

Use a voltage divider circuit for each threshold. Connect resistors in series between the sensor$\text{'}$s output and ground, tapping voltage at intermediate points.

Step $3$: Transistor Control for LEDs

Use NPN transistors to amplify the sensor$\text{'}$s signal and control LEDs:

Transistor $1$: Turns on the first LED for low humidity.

Transistor $2$: Turns on the second LED for medium humidity.

Transistor $3$: Turns on the third LED for high humidity.

Connect the base of each transistor to the output of the voltage divider through resistors $(1$k$$ to $10$k$).$

Step $4$: Add LEDs with Current$-$Limiting Resistors

$1.$ ad$$m:

Connect each LED to the collector of the corresponding transistor.

Use a $220$ resistor in series with each LED to limit current.

Connect the emitters of all transistors to the ground.

Ad$$m

Step $5$: Power the Circuit

Connect the voltage supply $($e$.$g$.,5$V$)$ to the sensor and the voltage divider.

Circuit Connections

$1.$ Low Humidity:

Connect the first threshold output $(01$V$)$ to the base of Transistor $1.$

When the humidity is low, Transistor $1$ conducts and lights up LED $1.$

$2.$ Medium Humidity:

Connect the second threshold output $(12$V$)$ to the base of Transistor $2.$

When the humidity is medium, Transistors $1$ and $2$ conduct, lighting up LED $1$ and LED $2.$

$3.$ High Humidity:

Connect the third threshold output $(>2$V$)$ to the base of Transistor $3.$

When the humidity is high, all three transistors conduct, lighting up all three LEDs.

Breadboard Layout

$1.$ Place the humidity sensor on the breadboard.

$2.$ Wire the voltage divider near the sensor$.$

$3.$ Place three transistors in the breadboard and connect:

Bases to voltage divider outputs $($via resistors$).$

Collectors to LEDs $($via resistors$).$

Emitters to ground.

$4.$ Connect LEDs to power through transistors.

$5.$ Connect wires neatly to avoid short circuits.

Circuit Testing

$1.$ Simulate different humidity levels by adjusting the sensor$\text{'}$s output voltage.

$2.$ Check:

$1.$ ad$$m:

Low humidity lights up only LED $1.$

Medium humidity lights up LED $1$ and LED $2.$

High humidity lights up all three LEDs.

can you draw me circuit for this explanation i must do it on breadboard but i could not understand where to connect the components there is missing information