Comparison between various programming circuit and common problems while making programmer

Before reading this article I want to tell this article is very childish but I think that not everyone study in IITs,NITs,BITs,and other good colleges where good guidance is easily available.So you can say That this article is childish but this is list of all problems that I found while making a programmer.

Comparison between various programmer circuit:

This is the programmer published in electronics for you magazine. Obviously this is working and a very fine circuit. Here IC 74LS244 is a buffer IC or line driver IC. Buffer performs following functions:

1) Isolates circuit from each other. In our case it isolates PC parallel port from microcontroller circuit and vise versa.

2) It improves current sourcing capability means now you are able to use longer cables.It's true than parallel ports are not able supply current over long distance and use of longer cable in common problem in making the programmer.But for us 20cm cable is enough don't use longer cables.

This one is another programmer circuit here instead of 74244 here another buffer IC 74541 is used. Both 74244 & 74541 have same function which is mentioned above. Both of these ICs are not pin compatible.

IN above circuit there is no buffer used only few resistors are used which limits the current and avoid damage to the pins of 8051 and wise versa.

This one is my circuit in which only connections are made between LPT port and microcontroller

Problems in making programmer:

1) BAD SOLDERING: first of all you must have some good soldering skills when you make programmer because most of the problem arises due to bad soldering.

2) USE OF BREAD BOARD: it may happen that you may get success on bread board but you are not lucky all the time.
3) WRONG CONNECTIONS: if you don’t get any success then check whether all the connections are okay or not.

4) DO NOT COMPLICATE STAY SIMPLE: there may be many fancy circuits available on the internet but chose the simplest one.(like MINE)

If you don’t get success in first attempt don’t be disappoint there are lot’s of people who don’t get their programmer work in first attempt .So just keep trying. Happy programming.