Simple Delay Timer Circuit | One Transistor DIY Project

in this video, I show how to build a simple delay timer circuit. With such timer you’ll be able to turn a light bulb or any other appliances on or off, for a defined period of time.
Components:
1. 2n7000 MOSFET
2. Button
3. 100 Ohms resistor (optional, protects button)
4. 470 k resistor
5. 47uF capacitor
6. 12V relay
7. 1N4007 diode.
8. 12 V LED strip (or something similar)
9. Wires.
10. 12V DC power source (battery, power supply, etc.)

[@Electronzap]

Nice!

[@richardgibbs00]

do you know the specs to make a 5 to 10 sec delay. i need to build one for my remote start on my truck. my country doesnt sell delay relays..thnks

[@anees607]

Nice

[@nooraq9889]

CHITTAGONG, great 👍

[@philipdetablan69]

can you add potentiometer to adjust the time delay?

[@stevethorson]

Is the capacitor charged when the button is pressed? Does the length of the button press matter?

[@renj6531]

what model relay did you use

[@fahimasghar6375]

Nice video Sir. Can you tell us why did you use diode across relay coil. Thanks

[@ElectricalPro]

Hi, it is called a flyback diode. It is used to eliminate sudden voltage spike seen across an inductive load when its supply current is suddenly reduced or interrupted. In other words, that diode protects MOSFET. In this particular circuit it may be excessive, because the current decreases slowly here, so no voltage spikes... but I decided to add it as additional protection for the MOSFET.

[@TechsScience]

Great!
Or you can use ic 555 instead

[@ElectricalPro]

Hi, thanks, yes, but it is simpler, just one MOSFET.
Also, I am not a fan of 555, once I made a generator with it, and at first it kind of worked, then it exploded (don't know why). Another bad experience with 555 had my friend who bought an overcharge protection device for 12V battery, but when voltage is 14.7V it suddenly starts to consume a lot of current and 555 burn out if you do not turn it off, and it was a factory-made PCB with 555 timer.
In my experience 555 often behave unpredictably... maybe it is just me.

[@zeeshanarif7201]

👍👍👍👍👍👍 can you work time punch machine

[@Exterminator131]

Блин, чувак, открой себе волшебный мир макетных плат! Этот навесной монтаж выглядит некрасиво, куда и как его монтировать, чтобы ничего не погнуть, не порвать, вообще непонятно! Разве что на витрину поставить и отправить на выставку!
И еще одно замечание: прежде чем, монтировать какую-то схему, нужно всегда объяснять принцип ее действия!