Showing posts with label Mains-Circuits. Show all posts
Showing posts with label Mains-Circuits. Show all posts

Monday, January 25, 2016

Flashing Neon lamp for Soldering iron

message: How can I make a flashing neon lamp - 240 volt AC

I have been trying for 3 hours ( R-C circuits) but no success. I want to include it in my soldering iron socket to show the power is on.

Mail from HJ of UK

These circuits may help, let me know if this works.

Neon Lamp Multivibrator ASCII Circuits
    I am sure a reading of above will help make your own. do not forget, i like a feedback.


    For the 1 Meg use two 470K in Series for 230V AC, that is safer. The circuit is live, so take precautions. The 0.47 Micro Farad can be increased if you want a slow flash. If the Mains 50/60 Hz Flicker is too much, the 1 uF can be made 2 uF, or use 4 - 1N4007 as a bridge rectifier.
    Flashing Neon lamp for Soldering iron
    From Schematics of delabs

    Flashing Neons (NE-2 / NE-51) second from top

    User Feedback -

    R1 of 4.7M and C2 of 0.47uF Works well at 230V AC. Try your own Combination. Less than 1M may damage Neon.

    Friday, March 13, 2015

    Mains Voltage Monitor

    i need a circuit design to detect generator voltage and display with LED for certain value of voltage. for example red LED"s for voltage under 180 V, green LED for 180-220V and Yellow LED for voltage above 240 V. i would like be glad if you would like to help me design it!

    mail from KB

    I have some designs that may do that easily. Have a look at them. We could modify them to suit your needs.

    First the 230V has to be brought down to say 2.3V with a transformer or attenuator. Then we have to measure it with LED bar graphs, choose color of LED as required. If the measurement unit is a sealed plastic box then it can be transformer less.

    Look at these first. Mains Stabilizer Circuit, In DMM Circuits see ....analog and 3-1/2 digital display for +/- 199.9mV. in LM3914 you can light up a bar graph or a single LED to show the Level.

    in Water Level Sensors see Fluid or Water Level Sensor using reed relays - circuit example

    DPM based on ICL7107 see AC voltmeter digital, 7107, pdf After you looked at all the circuits, Tell me how i can help you.

    DPM based on ICL7107


    i have seen almost all the source you show me. i got more explanation and also more confusion...!
    well, actually all i need is not too complicated but maybe its tricky for me. i got the idea about using voltage comparator via voltage divider, not using transformer like you said. it is more reliable and easier, isn"t? but again i got little bit trouble to design it!

    is it easy for you anantha? i hope you will give me best solution for it! if you dont have mind i will wait for your design as comparison, but not in hurry! Ok, thank you for your kind attention!

    mail from KB

    I will make a circuit for you as soon as possible. Do you need just 3 LEDs or more. do you have experience in using 230V supply safely as it can give shock. give me more details if possible.


    Again thank you very much for your attention on my question. actually it will be better to have 9 LEDS for 3 kinds. i have some experiences in installing 220/230 V but not expert, dont worry about that i will try as safe as possible.

    i would like to install picohydro for my garden with power about 300 watt using induction generator. it will be expensive and not comparable to use complete controller as well. so i wondering to have voltage indication to estimate voltage condition, or even you have experiences with picohydro or minimum requirement for it (controlling, safety) like overvoltage protection, etc. again i will be glad for it....!
    i will wait for your answers.

    mail from KB

    Can you please explain in brief what is picohydro and how induction generator is used. I have attached a circuit, It is not tested, It might do the job. You must have basic knowledge in building, testing and troubleshooting circuits.

    After a study of the circuit you can tell me more clearly your needs.


    Ok, induction machine can also used as generator if you at least:

    1. Drive motor faster than synchronous speed (slip = negatif)
    2. There is reactive power from outside (capacitor/Grid)
    I think you know it! in my case i used 3 phase induction motor with 1 phase output only (C2C connection),its more reliable and much better than 3 phase output for small power! its easy to build! any way, thank you for your design...!i will try to study it before i build.

    mail from KB

    The circuits you asked for with some explanation has been published here.

    Mains Voltage monitor using LM3914

    Simple Mains Voltage monitor


    Thursday, July 24, 2014

    Mains Voltage Stabilizer Step up Circuit

    i kinda found myself in a place where the voltage is so low (80v-110vAC) and i need to boost it up to 220v so what can i do? i have a burnt stabilizer (that is the electronics part) so i need the electronics circuit to replace the burnt one can Anybody help?

    post by FP

    here is a circuit i made for you, i am not sure it will work, i hope it will help you learn. part of these ideas are over 20 years old. Stabilizer Circuit

    Stabilizer Step up 230V AC 500VA

    This circuit is a design i did, not tested by me as yet. It can Stabilize Mains voltage to around +/- 10% . It can be used for both 110V AC or 220V AC inputs with modifications. The Output is 220V AC. There is an overload, under voltage and over voltage trip circuit. With some tweaks and modifications it might work.

    Solid-State Stabilizer Step up 110V AC

    This circuit is a design concept, not tested by me and i did it just to explain some ideas. The circuit uses opto-coupler MOC3041 of Motorola and the Triac BTA-16-600 of ST as a solid state switch or relay. It also uses the LM324 quad opamp from National Semiconductor which is low power and single supply. As the MOC3041 switches the Triac at zero crossover there is no inter-winding short of transformer on crossover hopefully, the control circuit is designed in such a way that more than one triac will not be turned on at a time, i would like you to give feedback.

    One more circuit, this is a bit complicated and it is not tested, it may not work that easy, just refer it to make your own design, it is just a bit of theory and my experience, i may be wrong at a few places.

    Electric Circuits


    Sunday, July 13, 2014

    Lamp Dimmer DC with L296

    I need a simple circuit to drive a 12v DC (4amp) light. But, it needs to dim to 25% over a specified amount of time. Basically it needs to hold at 25% (4v) for a few seconds then fade and increase to 100%(12v) , hold for a second then fade back to 25%.

    Here are the electrical specs: - Input 12vDC @ 5amps - Output from 4vDC to 12vDC (amp draw may be as little as 1 amp or as much as 4.5) - Only 1 potentiometer is used to vary the rate at which the voltage changes from 4-12 - It must increase and decrease voltage in a very smooth way, so that it fades the light to 100% and then back down to 25%

    mail from JR

    I have a circuit in my website that may serve your purpose, visit Power Supplies Section.

    There may be some documentation errors in my circuits. If you are used to building and troubleshooting circuits then it is ok.

    Switching Battery Charger with L296

    Switching Battery Charger with L296

    L296 is a switch mode power controller here. In this NTE327 or 2N5038 is used to boost the current output. This transistor is both high current and fast switching. U1A, LM358 measures the load current by reading the voltage across shunt R6 and compared to a current limit setting at R14 using U1B to give a load current control. R7-R8 give a voltage feedback for voltage limit.