In this post the circuit made for flashing a lamp uses the IC LM395 part and is cleverly designed to turn the lamp on and off at regular intervals.
It does this by using the IC LM395 power transistor along with some other basic components.
This is a really strong power transistor that is all in one piece.
It has cool features like protection against overheating and limits on how much current it can handle.
Even though the design is simple it works really well making it a great option for creating a flashing light that can be used for signaling or decoration.
The circuit takes advantage of the LM395s ability to handle a lot of current acting like a switch to control the lamps operation.
Circuit Working:
Parts List:
| Component | Specification | Quantity |
|---|---|---|
| Resistors | All 1/4 watt unless specified | |
| 100k | 1 | |
| 10k | 1 | |
| 150k | 1 | |
| 470k | 1 | |
| 47k | 1 | |
| Capacitor | ||
| Electrolytic 10μF 25V | 1 | |
| Semiconductors | ||
| IC LM395 | 1 | |
| Transistor 2N2222 | 1 | |
| Incandescent Lamp | 12V, 1A | 1 |
In the above circuit diagram the transistor Q1 acts like an oscillator that creates a series of regular pulses.
The way these pulses happen is affected by the components R1, C1 and R3 working together.
When the power supply is connected capacitor C1 starts to charge up through resistor R1.
Once the voltage on C1 gets high enough Q1 turns on for a short time letting C1 discharge and create a pulse.
This pulse then goes to the base of the IC1 LM395 through resistor R2 which makes the LM395 turn on.
When the LM395 is on it allows current to flow through the lamp L1 making it light up.
As C1 goes through its charging and discharging cycle this whole process keeps happening causing the lamp to flash on and off.
The circuit runs on a 12V DC power supply which gives it the energy it needs to work.
Note: You can connect an optional 1A fuse in series with the positive supply line.
Formulas with Calculations:
Below are the formulas with calculations required to design the Simple Lamp flasher Circuit using IC LM395
Oscillation Frequency Formula:
f = 1 / T
T = 0.693 * (R1 + R3) * C1
Substituting the values:
R1 = 100k ohms
R3 = 150k ohms
C1 = 10uF
T = 0.693 * (100k + 150k) * 10uF
T = 0.693 * 250k * 10uF
T = 1.7325 seconds
Frequency:
f = 1 / T
f = 1 / 1.7325
f = 0.577 Hz
Therefore, the lamp flashes approximately 0.577 times per second.
How to Build:
To build a Simple Lamp Flasher Circuit using IC LM395 follow the below mentioned steps for connections:
- Gather all the components mentioned in the above circuit digram:
- Connect the base of IC1 to collector of transistor Q1 through resistor R2.
- Connect the collector of 1C1 to positive supply of +12V DC.
- Connect emitter of IC1 to one end of L1 12V lamp and other end of lamp L1 to GND.
- Connect the base of transistor Q1 to emitter of IC1 through resistor R1.
- Connect the positive of capacitor C1 to base of transistor Q1 and negative of capacitor C1 to GND.
- Connect resistor R4 from positive supply and one end of resistor R5 in series and other end of resistor R5 to GND.
- Connect resistor R3 one end between resistor R4 emitter of transistor Q1 and other end of R3 to emitter of ICI .
Conclusion:
This easy but strong lamp flasher circuit that uses the IC LM395 is a great example of how to put together basic parts for useful purposes.
You can use it for things like decorative lights or warning signals.
Because it is simple and dependable, it is perfect for beginners and hobbyists who want to learn about electronics.
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