Simple FET Two Lamp Flasher Circuit

Simple FET Two Lamp Flasher Circuit connect same like simple astable multivibrator.

They make easy circuit for two lamps flashing one after other.

What is a FET Lamp Flasher Circuit:

This circuit using FETs mostly used for flashing lights or bulbs.

It also uses some other parts but mainly has few field effect transistors.

Circuit Working:

Parts List:

These FETs work in turn by switching two bulbs ON and OFF again and again.

The R and C values in circuit decide how fast bulbs blink which is about 1/3 times per second.

We can change flash speed easy by changing resistor or capacitor so circuit can fit many needs.

This makes it good for many different uses.

If we connect more MOSFETs in parallel we do not need parts that depend on current and we can use bigger bulbs.

Because of this the circuit can handle more power if needed.

Normal 12V to 14V bulbs with cold filament and 6 ohm resistor work fine in this circuit.

When power is ON with 12V it takes about 2 amps at start.

After that when bulb switches ON and OFF it only needs 200mA to keep working well.

Formula:

Frequency (f) of astable multivibrator can be found by easy formula:

f = 1 / (1.4 × R × C)

where:

• f is frequency in hertz Hz
• R is resistance in ohms Ω
• C is capacitor in farads F and it can be C1 or C2 based on circuit

Important Note:

This formula give only rough idea in some FET flasher circuits and mostly if design is more complex.

Things like transistor type, part accuracy and small leak currents can change real frequency.

How to Build:

Build a Simple FET Two Lamp Flasher Circuit follow the below mentioned steps for connections:

Gather Parts:

• Collect all needed parts like bulbs, power source, resistors, capacitors and FETs.

Place FETs:

• Put the two FETs properly on breadboard and be sure their pins are in right place.

Connect Resistors and Capacitors:

• Use the circuit diagram and connect resistors and capacitors with correct values for flash speed.

Change Flash Speed:

• Try different resistor or capacitor values to get the flash rate we want.

Connect Lamps:

• Connect lamp to circuit and ensure its 12V to 14V and has around 6 ohm resistance.

Power Connection:

• Connect power wires from supply to right pins on breadboard.

Check Start Current:

• Know that at power ON with 12V circuit pulls about 2 amps.

Conclusion:

Anyone who loves electronics can build a Simple FET Two Lamp Flasher Circuit and change it to match their needs.

Just check sometimes if all parts and connections are working good.

References:

Datasheet MOSFETIRF540