Simple Car Fused Tail Lamp Indicator Circuit

The article here shows how to build a simple circuit that can detect the taillights on your automobile are ON or not.

It uses a unique circuit component called as a resistor to find out if the lights are getting sufficient power.

If a light goes OUT the circuit will signal a problem.

This is a helpful tool to make sure your cars lights are safe and legal.

What is a Car Fused Tail Lamp Indicator Circuit:

An electrical circuit known as a car fused tail lamp indicator circuit keeps track of the functioning of an automobiles tail lamps and signals when a fuse connected to them has blown.

This circuits function is to alert the driver in the event that the tail lamp circuit has a problem which might be anything from a blown fuse to a broken lightbulb.

Circuit Working:

Parts List:

A key factor for calculating the value of resistor R is the projected voltage drop across Rx which should be around 400 mV to start the building process.

Take the case of tail lights for example, where two 10W 12V bulbs are connected in parallel.

1.7 amps is the result of using P/V to calculate the current flowing through the circuit.

Rx can then be calculated using V/I which results in a value of 0.24 Ohms.

A key component of this circuit is transistor T2 which is BC557.

T1 is activated by the 400 mV decrease across Rx which puts T2 in a cutoff state.

The current flowing through Rx is cut in half to 0.84 amps in the case of a tail light failure.

The voltage drop across Rx as a result is 0.2V.

The LED is illuminated because T2 receives a base current through R1 since this lower voltage is not enough to trigger T1.

It is advised to use a single detector circuit for a small number of lamps in order to provide a proper signal of light failure.

D1 and R3 work together across all sensors even though it is allowed to use a single LED for all detectors.

For proper working all T2 transistors collectors must be connected.

R3 should be 470 ohms in a 12V circuit to ensure maximum output whereas 220 ohms would be ideal for a 6V system.

Formulas:

Following are the formulas for Simple Car Fused Tail Lamp Indicator Circuit:

Calculate Resistor Values with formula:

Use the following formula to find the proper resistor values:

Rx = V/I

where,

• V is the voltage drop and I is the lamp current
• R1, R3 values are specified for the desired circuit voltage.

How to build:

To build a Simple Car Fused Tail Lamp Indicator Circuit the following steps are required to follow:

Connect Rx:

• To find out how much current the lights are using connect resistor Rx in series with the lamps L.

Connect Transistors:

• The BC557 transistor T1 should be connected so that the voltage drop across Rx affects it.
• When T1 is active connect BC557 transistor T2 in such a way that it may be turned off.

Add LEDs:

• Make sure the anode is connected to the collector and the cathode is connected to ground when connecting LEDs D1 in parallel to the collector of T2.

Connect R1:

• To restrict the base current of T2 connect resistor R1 between T2 base and collector.

Common Collector Connection:

• To enable a single response connect the collectors of every T2 transistor.

Connect R3:

• Limit the amount of current that passes through the LEDs by connecting resistor R3 in series with D1.

Power Supply:

• The circuit should be connected to the car battery power source at the proper voltage (12V or 6V).

Testing:

• Create a situation where a light fails to test the circuit.
• The matching LED should turn on in the event that a lamp fails.

Adjustments:

• Adjust resistor values if necessary based on requirements and actual data.

Conclusion:

This Simple Car Fused Tail Lamp Indicator Circuit offers a useful and efficient way to protect the smooth operation of car lights.

This circuit quickly recognizes and indicates any failure or outage in the connected bulbs by using a simple design based on voltage drop measurements across a resistor Rx.

A functional circuit for monitoring and signaling the condition of an automobiles lamps is ensured by following to certain constructing standards and formulas.