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Wednesday, February 27, 2019

24V and 25V Power Supply with 2A Current

I am looking for a 25V Power Supply with 2A current for my Application. A regulated supply.


Here is a simple to build regulated power supply. The two diodes are to boost the 24V to 25V DC. It uses regulator 7824 and TIP2955 PNP Transistor to boost current.

24V and 25V Power Supply with 2A Current


Thanks alot! Do you know of a good transformer manufacturer that has the one you specify? Also, is that "100V 3A" at the bridge the rating on the diodes? Also does the transistor circuit increase the voltage to the regulator so that it is 3 or more volts above the regulating voltage? Lastly, is your ground reference on the gnd of the regulator?

Wait, one more....this is + or - 25 volts correct?
Thanks alot!


1. choose a transformer with a close match of what is available.

2."100V 3A" at the bridge is the minimum diode rating also(or use 4 x 1N5408). "100V 3A" is also minimum bridge rating use a close match. make a bridge with 4 diodes refer my other circuits, there are many.

4. 22V AC leads to around 30V unrectified DC which is good, if the 30V becomes more, the heatsink needs to be very big.

5. the ground of regulator is lifted by (0.7*2) by 2 diodes to provide 1 V above 24V, as 25V regulator does not exist. the power supply 'neg' can be grounded or earthed,

6. the supply is a+25 V from ground or negative, but things are only relative.

7.if you need a dual supply 3 terminal , that is ground +25 and -25 then for -25 one more circuit using 7924 and tip3055(npn) has to be made.

8. use any high current pnp transistor (5A) you have put a heatsink with heatsink compound.


Monday, February 25, 2019

UPS and Inverter Schematics

Do you perhaps have an inverter schematic for a sinewave inverter or stepped squarewave using the SG3525 chip.

I'm also interested in connecting the inverter to the grid via a solar panel. I hope to reduce my electricty bill by pumping power into my 220v system. Do you perhaps have circuits to synchronise the inverter to the 50hz main.


Nice to get your email. .. Have you seen the circuits in my page....

Power and Energy Schematics

Switch fast from mains to inverter. The inverter is always on with the battery charged by the mains.

UPS and Inverter Schematics

The mains load is of two types

lighting low current 5A ??  and  heating high current 20A??

You should isolate both of them, the UPS is only for lighting. For heating you need a very big UPS, solar will not help, oil might.


I want to build a home UPS System. Uninterrupted power supply for computers and with Solar Cell Integration. I need some Schematics..


You have to design and develop these equipment, just a circuit or instructions will help you learn but you cannot make a robust product. Anyway have a look at these applications to learn ..

Sine wave Inverter 800VA

Learn about UPS here  UPS Power Inverter and DC to AC


Thursday, February 21, 2019

Making Coils and Transformers

Message - Can we make Coils and small transformers at home. I have copper wire and some lamination in my stores. - 2005


Making Transformers with good isolation and safety is a task for a firm and a home user must learn those skills by working in a winding company first.

As this is a general question many ask i am posting some educational pages. here...Coils and Transformers - Magnetics, Inductors, Chokes, Ferrites - Iron and Copper, Electromagnetism, Alloys, Insulators

Making Coils and Transformers

We have low frequency and high frequency transformers and coils in power electronics and electrical engineering. Then we have signal coils and transformers used in communications.

Low frequency transformers are made of a core of iron alloys in the form of insulated laminates to reduce hysteresis and eddy current losses. The copper wire insulated by a thin insulating enamel coat is used to wind the primary and secondary coils.

Coils and Transformers for SMPS, In Switching Power supplies and RF Circuits, the coils and transformers have many types of cores. Ferrites, Powder Iron, Air and others.

Producing wound components

This page provides practical guidance for students, staff and researchers at this University who need to wind their own inductors, transformers or solenoids. The types of wound components available, and their applications, are so varied that only general guidelines can be provided.

Compact Fluorescent Lamp (CFL)

Compact fluorescent lamps have some benefits in comparison with classic light bulbs. It is lower power consumption (to 80%) and much longer lifetime (5 to 15 times). Disadvantages are longer starts mainly at more expensive types, impossibility to use darker and price.

Practical transformer winding

In the good old times it was a matter of fact that every electronic hobbyist or technician would wind himself any power transformers he needed, and rewind any that burned out. Unfortunately, nowadays transformer winding is fast becoming a lost art, and I have seen many people despair about where to find some very specific transformer, or pull their hair out about the cost of having one professionally wound to specifications.

Winding Coils - Ham Radio

I used to view the inductors of RF circuits in books and magazines as problematic, often shunning any radio circuit having coils which are difficult to find . RF inductors of the correct value, unlike standard components, are not easy to buy, if at all. However, there are some great radio circuits around and it's a pity not to be able to reproduce them just because you normally can't acquire their coils off-the shelf. 

Inductors/Coils and Transformers and even Solenoids are magnetics. Core Type, Insulation Quality and Number of Turns and Thickness of Copper wire determine its function and performance. Making your own magnetic is the best way to understand their nature. Insulation/Isolation is the most important aspect of product safety in SMPS.