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Simplest 100 Watt LED Bulb Circuit

Simplest 100 Watt LED Bulb Circuit

The article discusses a very simple 100 watt LED bulb circuit using a few high voltage capacitors. The entire circuit could be built at a cost less than $25.

I have already discussed many capacitive type of transformerless power supply circuits in this blog, however all these suffers from a couple of issues, namely lack of optimal current output, and surge inrush vulnerability.

Using Capacitive Power Supply

Upon studying capacitive power supplies deeply I could conclude a few crucial things regarding these configurations:

Capacitive power supplies are quite like solar panels which work efficiently, at their maximum power point specs when they are operated with their open circuit voltages, otherwise the current specs from these units go through heavy losses and produce highly inefficient results.

In simple words if we one desires to acquire high current outputs from a capacitive power supplies at will, the circuit will need to be operated with a load having a voltage requirement equal to the maximum output of the system.

For example with a 220V input, a capacitive power supply after rectification would produce an output of around 310V DC, so any load assigned with a 310V rating could be operated with full efficiency and at any required current level depending upon the requirement of the load.

If the above condition is satisfied, it also tackles the current inrush issue, since the load is specified at 310V, an inrush of full input voltage now has no effect on the load and the load remains safe even during sudden switch ON of the circuit.

Analyzing the The Design

In the proposed 100 watt LED bulb circuit we employ the same technique as discussed in the above sections.

As discussed, if the input is 220V the load would need to be rated at 310V.

With 1 watt 350mA standard LEDs this would mean adding 310/3.3 = 93 LEDs in series, that's close to 100nos.

A single 1uF/400V capacitor produces around 60mA current at the above specified 310V DC, therefore for achieving the required 350mA more such capacitors will need to be added in parallel, to be precise a total of 350/60 = 5 capacitors, that could also be a single 5uF/400V but should be a non-polar type.

An NTC thermistor may be added for extra safety, although it may not be critically required.

Similarly a resistor could be also included to provide extra bit of safety from fluctuating voltage conditions.

The resistance value may be approximately calculated as R = Us - VFd/I = 310-306/.35 = 10 ohm, 1 watt

For a 120V input, the above specs would simply need to be halved, that is use 47nos of LEDs instead of 93, and for the capacitor a 5uF/200V would be enough.

Circuit Diagram

The above diagram can be additionally safeguarded from surge inrush voltages, and mains fluctuations by adding a 10 ohm limiting resistors and a zener diode, as shown below.

Here the value of zener diode should be 310V, 2 watt

Improved design with current control

The following circuit is a foolproof circuit design that will never allow the LEDs to come across a stressful condition. The mosfet and thee associated current control ensure 100% constant voltage and constant current for the connect LED bulb chain.

The number of LEDs in the chain can be adjusted as per the selected voltage, or conversely the voltage can be adjusted as per the selected number of LEDs in the chain.


About the Author

I am an electronic engineer (dipIETE ), hobbyist, inventor, schematic/PCB designer, manufacturer. I am also the founder of the website: https://www.homemade-circuits.com/, where I love sharing my innovative circuit ideas and tutorials. If you have any circuit related query, you may interact through comments, I'll be most happy to help!

142 thoughts on “Simplest 100 Watt LED Bulb Circuit”

  1. Thank you sir ,sir where i connect +ve input and -ve input ? Is the +ve can be connected in capacitor side? What is the specification of zener diode?

  2. Thanks sir, sir I can you help me by using smps ? Can you provide me that full circuit diagram and all specification of all components? Sir plz help me I am so excited about this project.

      • Thanks Sir,Sir I want to do a 100 watt LED lamp with 1watt LEDs .sir please give me proper circuit diagram and provide me full specification of all components used in this project. Sir plz help me kindly I am so excited to perform this project. Plz sir

  3. Thanks sir, Sir I am very excited to do this project sir can you help me? Can you provide the actual practical circuit diagram of this project , with all components and all’s specification. Sir plz can you send me with full description?

    • Ritesh, I have undated the diagram, but please do it at your own risk, because mains current is always dangerous and you cannot predict it 100%.

      If you want 100% guaranteed results then it is always better to go for an SMPS based power supply or a transformer based power supply.

  4. Sir,As shown in circuit diagram can I connect the zener diode in parallel with 10uf 400v capacitor ? What’s the specification of zener diode ?where can I connect the heat sink and what’s the specification of heatsink

    • yes you must connect it in parallel to the 10uF/400V cap. The zener value should be equal to the total forward drop of the LEDs in series. Heatsink will need to be determined through practical experimentation

  5. Hello Sir, thanks for your support , Sir can I know where the ntc is connected in +ve of input or in -ve of input ?and what is the specification of zener diode? and where I can use to the zener diode?sir plz kindly respond me.plz help me out

    • Ritesh, NTC can be connected anywhere in the line, either in the positive line or the negative.
      zener diode can be connected parallel to the filter capacitor.
      but make sure to connect a small value resistor, may be a 50 ohm 2 watt in series with the NTC.

  6. Dear.. how are you sir i hope your healthy n fir ..
    can can you provide me the circuit diagram of *manual heat sealing machine*

    • Nazim, the procedures involved are purely mechanical so I won’t be able to help you with it, since my expertise is lies only with electronic circuits

  7. Dear Swagatam sir
    Simplest 100 Watt LED Bulb Circuit.

    1Watt LED
    Forward current: 350mA
    Forward Voltage: 3.2V~3.4V in average (3.3V*93Leds= 306.9V),
    In india we are getting Indian power supply 240V 50Hz then how this circuit working.

    My dought is input voltage is lower around 220V~250V and output Voltage is Higher (3.3V*93Led)=306.9V… how ita working sir

    • Hello Nazim, the 220V is the average value of the AC, alo called the RMS, the peak value of this 220V AC is always around 310V.

      when we rectify this 220V with a bridge and filter capacitor, the 310V is produced and sustained at the output by these components, therefore the output that we get is 310V DC instead of 220V AC.

  8. I think 5uf is sufficient for led if the brightness is not getting sufficient then it may b led fault or any other fault in my circuit sir ? Im i correct sir

    Im not get 310v 2watt zener diode in my local market so i let it and only 5uf +1uf again add totall 6uf then the above said situation happen.

    Did zener diode controls the volts or Ampere sir?

    • did you connect a large heatsink with the LEDs? at 300mA the LEDs can get immensely hot and will blow within a minute.

      without a zener the LEDs can burn with a slightest mains fluctuation.

      zener will control voltage and will prevent rise in abnormal current consumption.

  9. Dear Swagatam sir,
    If i want to run 1watt 350mA led on 12-0-12 , 5Ampere transformer.
    Q1 :- How can i run 1watt 350ma leds?
    Q2:- What changes i have to done in above 100watt bulb circuit?
    Q3:-how many leds can i operates with 12-0-12 5ampere transformer with out any problem to enter set?

    In the previous 93led circuit i have add one 1uf/400v non polar capacitor then i give supply after some time 5to10mints leds become slowly dim by dim i think “1uf producing 70mA (70*5=350mA)

      • Hello sir,
        I have made this tranformerless circuit using MB10S bridge rectifier. I have used 250v 1.1uf non polorised capacitor and 250v 10uf polorised capacitor with 470 ohm 1 watt resistor at output with series of 52 leds string. But at output i am getting only 37mA. When i need 60mA. When i tried using 250v 2.2uf non polorised capacitor it became so hot. And other thing is i have some size ristrictions for this driver so if i use 400v non polorised capacitor then it will be so big and will not fit in. So can you plesse give me dome solution over this problem?
        Thank you.

        • Dipan, to get 60mA you will need a 2uF/400V capacitor. 400V is required for guaranteed safety to the capacitor so it is a must. For smaller size you can use 250V but that will not ensure a 100% safety for the capacitor.

  10. Dear Swagatam sir
    Simplest 100 Watt LED Bulb Circuit.

    (Did i need to place between “6uf/400v ….(310b 2watt zener diode ?)…… 10uf/400v) right sir

    • Dear Nazim, yes connect ii across the same points where 10uF/400V capacitor leads are connected, anode of zener to minus of capacitor, cathode to plus pin of capacitor.

  11. Dear Swagatam sir
    Simplest 100 Watt LED Bulb Circuit.

    310V 2 watt zener
    in the above design circuit where i have to place the zener diode

    waiting for your great replay sir thanks a lot sir. thank you very much sir

  12. Dear Swagatam sir.
    Simplest 100 Watt LED Bulb Circuit,

    Can i get sufficient brightness if i add below two parts to circuit
    part 1:- 1uF 400V Non-Polar Metallized Film Capacitor
    part2:- 310V 2 watt zener (it shoud be add on 1n4007 diode brige im i correct sit and i dnt know how to connect the position )

    • Dear Nazim, obviously if the each LED gets 3.3V at 300mA then all the LeDs will illuminate at optimal brightness.

      dividing 310V with 93 LEDs gives 3.33 which is the right voltage value for each of the LEDs.

      and if a 6uF cap is used it will provide the required 300mA to the whole string. if it doesn’t then the problem could be somewhere in your parts or the connections.

      310V zener is only to make sure the max voltage to the LeDs does not go above 310V, which can otherwise damage the whole string.

      however if the supply voltage drops below 300V DC (210V AC) then the LEDs will become dimmer…at 200V (145V AC) the LEDs will almost off.

  13. Dear Swagatam sir
    Simplest 100 Watt LED Bulb Circuit

    1uF/400V capacitor produces around 60mA (as i read in your blog if we add 1 or 2 more capacitors it will produce above 350mA im i correct sir)

    A single 1uF/400V capacitor produces around 60mA current at the above specified 310V DC, therefore for achieving the required 350mA more such capacitors will need to be added in parallel, to be precise a total of 350/60 = 5 capacitors, that could also be a single 5uF/400V but should be a non-polar type.

    • Hello Nazim, yes you can add a couple of more 1uF capacitor to increase current for the LEDs, but this can make the Leds vulnerable to slightest voltage fluctuations and burn them. 1uF will practically give around 50mA…not 60mA which may be true only as per the formula.
      the capacitor should be a non-polar.

  14. Dear Swagatam sir
    Simplest 100 Watt LED Bulb Circuit

    If i add “1uf 400v” two more capacitors in my old circuit can get sufficient brightness sir

  15. Dear Swagatam sir
    Simplest 100 Watt LED Bulb Circuit
    Thanks you very much for give each and every part information finally i have successfully turn on led bulb with my partner jatin thanks a lot “SWAGATAM SIR AND JATIN” but a led not giving sufficient brightness can…

    Can you give information about “Capacitor Based LED Tubelight Circuit Using 1 Watt LEDs” https://homemade-circuits.com/2014/07/capacitor-based-led-tubelight-circuit.html

    Is tube light me use kre hue parts ki information dejiye na identify karne k lye plz
    Thanks a lot sir

    • Thank you dear Nazim, I am glad you could make it successfully….the illumination can be increased by reducing the number of LEDs in series…if you use 93 LEDs, the brightness will be maximum..also the 5uF capacitor will give only 250mA current which is not full current for the 1 watt LEDs…so you can add one more capacitor in parallel to make it 300mA, but this will make the LED more vulnerable to surge currents…

      the details of the other tubelight is discussed in the comment section, please check it in the comment discussion. and also it is given in the last PCB design

  16. Dear Swagatam sir
    Simplest 100 Watt LED Bulb Circuit
    below the four parts images from url once see and say me there are correct image of parts sir,

    1.10uf 400v (1 pieces ) ( Image url )
    if i don’t get 10u 400v can i take 10u 450v

    2. 1uf 400v (5 pieces should be connected in parallel series )(Image url )

    3. NTC Details (Image url )
    (if ntc not available in local dealer can i leave it sir)

    4. 1watt 350mA led (image url )

    waiting for your great replay sir thanks a lot sir for proving me each and every information with out hesitating . thank you very much sir

    • Hi Nazim, all those examples are correct, you can go ahead with them.

      the LEDs will require a large heatsink, so please do not forget to mount them on a hetasink.

  17. Dear Swagatam sir
    Simplest 100 Watt LED Bulb Circuit
    Went to local spare parts dealers and show circuit diagram did not understand . All they asked me image or images of parts r types of capacitors and Resistor 1M Watt? And NTC details so i aked you images sir plz help me to success in this making bulp
    1.10uf 400v {image or capacitor type}
    2. 5uf 400v {image or capacitor type}
    3.1M (Resistor Ohms and watt)
    4. NTC Details {image or details }

    Local dealers give me perfect by seeing circuit diagram 1watt led and diode 1n4004 this two item only i have got the above mentioned 4parts asking more details

    Can this bulp run on indian voltage India 240v 50Hz im waiting for your great reply sir thanks a lot sir for providing me a lot of information. Thank you thank a lot

  18. Simplest 100 Watt LED Bulb Circuit.

    dont mind sir asking too much because i am not a (Electronic & electrical engineering ) Background student im a commerce student ..after seeing your website i plan to work in this circuit design .
    i have bought 1w 350mA leds with heat sink plate
    i need below parts images to work in this

    i need some images of parts
    1. 10uf 400v {image needed}
    2. 5uf 400v {image needed}
    3.1M (Resistor Ohms and watt)
    4. NTC Details {image needed}
    can you provide me sir please sir
    Email: nazimhussainisyeds@gmail.com

    • Nazim, If I show you the image then you may go strictly as per the image, which can make things more complex so it’s better that you only take the following parts list and show it to the shopkeeper, he will be able to guide you and provide you the materials:

      1) 10uF/400V electrolytic capacitor – 1no
      2) 5uF/400V can be built by putting 5nos of 1uF/400V PPC capacitors in parallel, this capacitor is normally labelled as 105/400V PPC or MKT.
      3) 1M 1/4 watt CFR, – 1 no
      4) NTC = 11mm, 5 ohm type 1no, or any suitable will do.


  20. I assembled the above circuit with 83 1w leds and 2 x 225k capacitors and used one inductor coil also in the circuit. It is working superb. Many Thanks for your help. VG KRISHNA from Hyderabad.

  21. Shopkeeper recommended this to me. NTC 10S100L would use this instead of the NTC 5D-11Tell us your advice
    Waiting for your replay thank you sir

  22. Sir Namaste my sincere thanks for your advice.

    There is another suspect.
    Can I use this NTC 10S100L instead of that you have to NTC 5D-11 . Would it be much safer if I use this?
    Can I use it to circuits in your blog?

  23. Sir,
    In fact am receiving very greatly help from your blog. And most significant article be present you converse with each person who needs proper supervision. I’m so beholden of this blog and you

  24. Sir,
    Good day to you can i use this if I have to do 25 1WATT LED. If so what changes need to?

    I learned a lot in your blog. Five circuits were successfully accomplished by using your blog. Thank you sir

    • Thanks Satheesh, the number of LEDs should be around 80 to 100….25nos could be risky because its total forward voltage drop may be much lower than the AC level.

      If you intend to have a 25 watt output in that case you can try using lower wattage LEDs so that you can increase their quantity to around 80 to 90 of them.

  25. Hello sir

    I wish to create a light of 3w 30 white leds with ac 220 supply. Ive bought the leds & heatsink( 30 led in series ). Please guide me with the circuit diagram with capacitor, resistors etc & how to go about. Please..i

  26. i want to light 18 ( or 20 ) led smd bulbs (10 watt each) in series with direct mains supply (220 volt ac) using rectifier and some resistance.
    each led is rated at 12volt, 1 amp.
    i don't want to use input capacitor (to make it simple).
    i can increase led numbers to reduce heat production.
    can this arrangement run using half wave rectifier ??. if we use half wave rectifier then what is the risk, i have 6A4 MIC RECTIFIER rated at 420 volt 6 amp.

    • the input capacitor is compulsory, otherwise your LEDs could get damaged instantly anytime. dividing 230 by 12 gives 19 so probably you could use 20nos of 10 watt LEDs in series.

      The input capacitor could be rated at 10uF/400V (non-polar), and the set up should be exactly as shown in the above article.

      half waver rectification will lower the illumination of the LEDs…but there's no risk in it.

  27. Hi Swagatam Sir,

    This is Suraj. Thanks for yours help. I tried with a 0.68mf input capacitor instead of 0.33mf and now the leds light much brighter than earlier. Thanks.

  28. Hi Swagatam Sir,
    I'm Shrinivas Mohod, an amateur photographer. I use 1000W halogen sungun to get desire light. Now I want to replace this gun with LED gun. I've enquired in market, it's cost goes very high comparing to halogen sungun. (about Rs. 7k to 8k where halogen falls at Rs. 550) I've made a couple led circuits given on your blog. Now I want to make an LED light exact like as LED street lamp. Is it possible to make it with the 5W LED module (27 nos) on direct mains 220 (I don't want to use heatsink)? Actually I have sent a plot of light on your facebook timeline. Please check it once, please guide me as possible as you can.
    Waiting 4 reply.
    Thank You so much sir.

    • Hi Srinivas,

      you can use the idea that's explained in the above post and build it for your requirement. I would recommend using 1 watt LEDs instead of 5 watt since 1 watt LEDs are easier to handle.

      But high watt LED will definitely emit significant amount of heat and you would need to install these over a correctly rated heatsink.

      If you are not interested to use heatsink then probably you would have to employ twice as much as LEDs, for example for getting 1000 watt illumination you would require 2000 numbers of 1 watt LEDs to produce an equivalent amount of light without using any heatsink.

  29. Hi. This is Suraj. Using your circuit diagram I have created a serial light with below specification. All the bulbs in the serial are lighting but they are not as bright as expected. So what further changes I need to do with it. Please help me. Waiting for your reply.

    Power Supply 220volts
    5mm 20mA 3.2v x 95 white leds
    Input Capacitor 334J 400volts POLYESTER TYPE
    470K 0.25w resistor
    2nd Capacitor 10 Mf 400 volts ELECTROLYTE TYPE
    NTC 100 ohms 0.5watt resistor

    • Hi Suraj,

      334 = 0.33uF which is quite low…

      try a 474 that's 0.47uF…if still it doesn't provide sufficient brightness, increase it to 0.68uF

  30. can i use this ckt for run 100 led of 8mm ( vf=3.2v) in series.
    what would be input capacitor value for this ?

  31. For all the series you can use 5uF/400V for the input capacitor, since current is same for all of them.

    C2, and NTC are not critical, C2 can be any high uF capacitor rated at 400V, NTC can be a 11mm, 5 ohm NTC as shown below


    use an inductor also in series with the LED string by winding 200 to 500 turns of 0.5mm super enamel copper wire on any iron core, such as an iron bolt or a ferrite core will also do.

  32. Sir
    I used……LED .5 watt ,3.5V,170ma, 90 no.in series only change is 3uf cap.
    LEDs are glowing but not satisfactory ….less than 40 watt tube light .so arranged 3+2uf cap current increased from 40ma to 50ma….light increased but not up to mark..so added 2uf ..but current is below 60ma….
    Input voltage is 225 to 230 AC…Out put is 320V…….on load 265V
    Voltage across cap is 50V,………and on load it is 27 V AC
    So please help me….whats wrong …..

    • Dastgir,

      connect the ammeter directly across (+)(-) of the supply, this will show you the actual maximum current capacity of the supply.

      if it's not 60mA per 1uF then your capacitors could be of bad quality, you may want to change it in tat case with a god quality ones.

  33. Sir can I use aluminum frame for 1 watt led for above circuit as u said for to paint and firmly pressed the LED on frame that process can also be applied for this circuit

    • an aluminum plate can be used as a heatsink with the above circuit, but since the above circuit does not have a current control feature, therefore the heatsink should be sufficiently large and if possible should be operated under a fan

  34. hi Swagatam i m from Badlapur. This is not my comment but can u pls tell me where can i get this type of raw material for led circuits thanks

  35. hello swagatam can u plz tel me how can we calculate zener volt and watt?
    i m using 20 led, 40 led ,and 60 led in 3 diffrent circuit…..plz help me with zener value …

    • Hello manj, the zener volt should be a few volts above the total forward voltage of the LEDs and wattage twice that of the LED series wattage.

      If we take the first example in your case, it would be as follows:

      zener voltage = 20 x 3.3 = 66V so it should be 80V.

      zener wattage = 2(wattage of the LED used)

      example if 1 watt LEDs are used then the wattage of the zener would be

      2(1) = 2 watt

    • ….sorry the zener wattage will be = capacitor max current output x (supply V – LED fwd V)

      if we assume the caapcitor current to be 500mA, then for the 20nos 1 watt LEDs it would be

      0.5(310 – 66) = 122 watts

      to avoid this huge value, the difference between the supply and the LeD fwd voltage should be as small as possible.

  36. Bro, i understand your explanations. I know that in case of transformerless designs it is preferred that the source voltage and load voltage be identical to avoid the surge issues etc.
    but i wish to drive minimum number of leds with full brightness for ensuring my light efficiency and also the less cost. 50 leds will cost me a lot of money. waiting for your suggestions.

    • Bro, in that case you will have to go for a SMPS unit, because with a capacitive PS and few LEDs you can never achieve the desired results

  37. Dear swagatam ! u told that 25, 1w leds would not give optimal illumination, but my concern is to replace my old tube light(28w) in my bed room. in that case 30 , 1w leds should give sufficient light in my bedroom only. your concern?? what glue should i use to stick leds on heatsink and how??

    • Dear Pritam,

      for ensuring optimal response the supply AC V spec must be close to the load V spec.

      25 x 3.3 = 82.5V, and the input is 220V so the difference is wide that's why you wouldn't get an optimal output….but adding 5 more LEDs may compensate the inefficiency.

      You can use 40/50 LEDs with a 1uF/400V capacitor, this would provide nearly 25watts of light output without heating the 1 watt LEDs and you wouldn't need to put the aluminum strip.

  38. for heatsink i am using alluminium channel used for glass windows. i am clamping the 1 w led by fevikwik on the alluminium panels.. it should sink all the heat..

    • sticking with fewikwik is OK but not the recommended method, may just work, press it hard to reduce the film thickness between the LeD base and the aluminum.

  39. hi! i want to drive 25 pcs of 1w led usinf this ckt. just replacing 5uf with 3.3uf, removing ntc, adding 10uf 450v cap at the rectifier o/p and a zener diode of (25*3.3)=82.5v 1w for protection and a 500ma fuse at the i/p.. will it be a safe idea??pls reply

    • Hi, with 25 nos of LEDs the efficiency of the circuit will drop by a lot and the illumination will not be optimal. for ensuring optimal response the supply AC V spec must be close to the load V spec.

      NTC is a must in any case and must be included, rest of the modifications are OK.

  40. Please help with a very small but important project.
    LED Latching Circuit using Transistor.

    Power Supply: 3 or 6VDC
    Load: 3 or 4 LEDs (I can calculate resistor sizes needed)
    On Switch: Momenatry
    Separate Off Switch, also Momentary

    I'm looking for a SIMPLE transistor circuit that will turn on LEDs when Momentary ON Switch is depressed and STAY lit until the Momentary OFF Switch is depressed. This should be a simple ON/OFF circuit that latches in the ON condition until the OFF Switch interrupts the latched circuit. I have little knowledge in PNP. NPN, MOSFET devices, so I would very much appreciate it if you would select a small, inexpensive transistor for this circuit..

    • Hello Pritesh, for 95 LEDs use 0.33uF/400V for the input capacitor, NTC may not be necessary, rest all can be kept as shown in the above diagram.

  41. Hello sir
    I've created the rope light & is working fine. Thanks to you.
    Now for 95 leds of specification 5mm 20mA 3.2v white what further modification would be required in yours circuit. Will the value of resistors, NTC, etc will also change?
    Waiting for yours reply.

  42. Hello sir

    I wish to create a rope light of 50 white leds with ac 220 supply. I want to replace all bulbs in the rope light with leds, as bulbs fuse now & then. Ive bought the leds. Please guide me with the circuit diagram with capacitor, resistors etc & how to go about. Please…

    • Hello Pritesh, you can use the same circuit which is shown in the above article, if the LEds are 5mm type then replace the 5uF capacitor with a 0.47uF/400V capacitor. that's all

      connect all the LEDs in series and connect the ends as described in the above article.

  43. hello sir,
    please suggest some initial and basic ideas for starting led tube lights and emergency lights production business regarding initial capital manpower space and other requirements as nobody other can not suggest better than you. what basic problems i can face while starting business and setting up it. your suggestions will be very appreciative and beneficial.
    sunny pawar

  44. Hi! Sir, it's been a long time. Please sir,i have a question. I checked the datasheet of transistor 2N3055 and it said that Collector current(max)=15A, Collector-emitter voltage(max)=60V, Collector-base voltage(max)=100V and Emitter-base voltage(max)=7V. I want to use one of this transistor to design a class A amplifier circuit that can receive a power supply of 45V. But i want to design the voltage divider that can set its base reference voltage, and i want the output of the voltage divider to be around 35V. But my fear is that the 35V would be greater than the 7V emitter-base maximum voltage rating. Please how can i calculate the R1 and R2 that will form the voltage divider network to produce 35V from the 45V power supply without damaging the transistor? I tried it using a voltage divider that was producing 18V to the base of 2N3055 from a 20V power supply and it worked fine, but nw i want to increase the power supply to 45V and the voltage divider's output set to produce 35V but i want to confirm it is will be right and proberbly the right value to use for R1 and R2 for this result. Please sir, show me in full calculations on how you calculated their values. Thanks!

    • Hi Jideofor, Although I am not sure how and what you are trying to implement, because there are many class A amplifiers circuits online perfectly optimized and tested which you can simply copy.

      7V is the emitter-base voltage, not base-emitter, so please do not confuse them with each other.

      You'll need to take care about base-emiiter saturating voltage which is 1.5V for 2N3055

      The formula for calculating the base resistor of any BJT is given in this article:


  45. sir ui make the circuit of fm bugger circuit from electronichub site .i sed the values of 47.8uH and 50pF of tank circuit but no result at proteous .canu guide mu?????

  46. Sir you are getting it all wrong. I said the Ic 4863's outputs are not ground compatible, and getting the outputs with respect to ground will make the ic to produce 2v instead of 8v, because its speakers are not connected with respect to ground (the outputs of the Ic 4863 is just like the output of TDA7560, non of them came from GND) and it is producing more than enough power to drive the TDA7560(without connection to ground. But from ground, the output will reduce. Just guide me on how to configure the op amp lm324 as preamp

    • Jideofor, single-ended amplifiers will also respond to its output directly. It's important to confirm first whether your amp is alright or not.

      I do not have any idea how to make a LM324 driver stage for it.

  47. Ok sir. I measured the output voltage from the Ic 4863 that went to its speakers and it measured upto 8v(while music was playing), but when i measured the ouputs with respect to ground, it would produce at most 2v(while music was playing). And if i integrate a speaker to its output with respect to ground as you suggested, the music is usually low. My question is can i add an op-amp based preamp at its outputs to boost the outputs of the Ic 4863 from 2v to 8v so that the signal coming from its outputs with respect to ground would be the same as the one coming out of it without respect to ground? So that when i feed the 8v to the TDA7560's inputs, it will reach 51w. If it is possible, direct me on how to connect the following pins of the Lm324 to start functioning as the voltage amplifier(non-inverting inputs, inverting inputs and outputs) of all its stages because i want to make use of the whole 4 x op-amp stages inside the lm324 to feed the TDA7560 since its inputs is 4 in number and the outputs of the Ic 4863 with respect to ground is also 4 in number. Please direct me on how to calculate the feedback resistors too for defining the lm324's voltage gain, and finally the right supply voltage to use for the lm324

    • LM4863 is a powerful audio amp by itself and it's output should be more than enough for driving LM7560…no need of any external stages.

      your construction may be incorrect somewhere, check it properly and as I suggested earlier you should use the recommended PCB for making the amplifier for eliminating any chances of faults and doubts..

  48. Hello swagatam…. Its been a while now and that's because I av bin so busy dis year. Pls I need ur help again. I want 2build an LED circuitry that is efficient at consuming very low power of 60w for 11 rooms in a house. Which will b better, a JOULE THIEF or PWM circuit. Thankz

    • Hello tonisage,

      a joule thief or a PWM both are efficient depending upon the dimensions of the intended input/put ranges.
      these are efficient because they do not waste energy while operating, however the input power will be always equal to the output no matter which circuit is used.

      If your application is at mains AC level, you can opt for a PWM driver circuit.

  49. Sir i am having a challenge on this: i have an Mp3 with Ic 4863 that is dual channel( two outputs with speakers, rated 3w, 4 ohms) i want to remove the speakers and replace it with any of the input pins of the Ic TDA7560(so that the TDA7560 can amplify it further). But my problem is that the output pins from the Mp3 that went to the 3w, 4 ohms speakers has none that is connected to ground(GND), but the inputs of TDA7560 is ground compatible(ie, its inputs are connected with respect to ground; GND). My question is how can i do this because if i should go ahead and connect it as required by the TDA7560 input schematic labelling it would amount to grounding two of Mp3's output pins wich i think will be harmfuld to its Ic(4863). Please direct me on what to do. Thanks!

    • Jideofor, just make the grounds of the TDA7560 and 4863 common, after this you can simply integrate the inputs of the TDA to any point that may be producing the audio in the MP3 system

  50. Please sir, Is it possible to get 4 ohms speaker from connecting 2 x 8 ohms speakers in parallel?[ie, R=(R1)(R2)/R1 + R2 ]. For instance, the IC, TDA7560 can produce 4 x 45w in 4 ohms speaker according to its datasheet. So does it mean that if i connect 2 x 8 ohms speakers in parallel, then connect it at the output of the IC, wil it produce the same 45w power as it would have done in a single 4 ohms speaker? Please help! ThanksPlease sir, Is it possible to get 4 ohms speaker from connecting 2 x 8 ohms speakers in parallel?[ie, R=(R1)(R2)/R1 + R2 ]. For instance, the IC, TDA7560 can produce 4 x 45w in 4 ohms speaker according to its datasheet. So does it mean that if i connect 2 x 8 ohms speakers in parallel, then connect it at the output of the IC, wil it produce the same 45w power as it would have done in a single 4 ohms speaker? Please help! Thanks

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