Few Common Mistakes While Working on Electronics Workbench like Reversing Power Supply etc.

Whether you are an electronics hobbyist or while doing your academic project, you must have worked with electronic circuits and soldering iron, etc. and in the process you must have done at-least a few mistakes which might have caused some loss to you. So, here I am listing a few mistakes that you need to take care of while dealing with circuits.

I usually spend my free time training students on electronic design and also help them do their projects. This is how I usually spend my weekends. After training about 50 people, I found that many of them (including me) made same mistakes in the beginning while working with circuits on the workstation. So, in this article I have listed those frequently occurred mistakes hoping that you will be careful next time when you work.

Common Mistakes Occur While Working on Electronics Bench:

1. Attaching Batteries

Attaching Batteries

Batteries are the most common source of power supply for most of our electronics projects. Often in many projects, batteries are preferred to be used as DC power supplies than using the complex way of converting the AC supply to DC power.I have seen many people join batteries head on playfully sometimes without even noticing what they have done. If you give two PP3 batteries to a person and leave him for some time, most probably he will have a curiosity to join them together due to their symmetrical nature. But never do that! That can damage your batteries.

2. Leaving Wire Joints Open

Leaving Wire Joints Open
Leaving Wire Joints Open

Leaving electrical wire joints open can cause short circuits and the consequences can be very dangerous. It can lead to short circuit and may not only damage your circuit but it can sometimes lead to a great disaster. I need not tell you how disastrous short circuit can be. Also if you dare to hold the uncovered wire joint with bare hands, it can cause current to pass through your body (Remember your body is a perfect conductor) and you are in the risk of getting an electric shock. So, always cover the open joints with an insulating tape.One more tip is, make joints at unequal lengths so that it can reduce the probability of getting shorted.

3. Misplacing Soldering Iron

Misplacing Soldering-Iron.
Misplacing Soldering-Iron.

Misplacing the soldering iron can cause a lot of damage. If you put it beside any circuit or wire by mistake, you may get the wire short circuited or the circuit burnt. The solder is actually the molten metal and if it comes in connection with the wires accidently, it can short circuit the wires and also the hot molten metal can burn the circuit. I can strictly recommend you to use a good soldering iron stand and never forget to place your iron in the stand. Also never ever try to hold the soldering iron tip with bare hands.

4. Soldering for a Long Time at the Same Place

Never solder a single pin for a long time. Components get overheated and may get burnt. Also for your circuit to look presentable, remember to solder the pin in a effective way so as that the solder doesn’t spreads to nearby places, i.e. to other holes on the PCB.  If you feel the joint is not getting soldered, then try applying some flux. If you are soldering any heat sensitive component, then it is recommended to use a socket for it. If you need to solder it directly, then use a heat sink at the soldering point so that heat is dissipated quickly and prevents the component from overheating. A simple crocodile clip will also work as a heat sink.

Read the post How to Practice Good Soldering Method to get an idea about soldering.

5. Reversing Power Supply Polarity

Reversing Power Supply Polarity
Reversing Power Supply Polarity

Most of us might have applied the power supply with wrong polarity at-least once mistakenly. This can damage the circuit sometimes. To avoid this, I recommend you use Elements instead of berg sticks as shown in the figure for connecting power supply and use naps for the batteries. For protecting your circuit from damage when reverse polarity is applied, you can use a diode with sufficient power ratings in reverse bias connected to the source pins.

6. Touching CMOS ICs with a Charged Hand

Touching CMOS ICs with a charged hand
Touching CMOS ICs with a charged hand

CMOS ICs are very sensitive to static charge. They may get damaged when static charge is applied. Our hands are usually charged when they get rubbed with other materials like clothes. If we touch CMOS ICs with our charged hands, it may damage the IC as our hands are conductors and a static charge passes through out body. So, next time when you are touching a CMOS IC, it is recommended to first touch a grounded metal like legs of an iron table, etc so that the static charge is discharged. These days, some ICs have inbuilt protection against static charge but still it is recommended to earth your hands before touching as the static voltage buildup on our body can be unbelievably high.

7. Removing ICs from the Socket without Using a Lever

Removing ICs from the socket without using a lever
Removing ICs from the socket without using a lever

Removing an IC from its socket with our hands can cause the pins to bend or break. If you want to remove an IC, it is recommended to use a lever like a screwdriver as shown in the figure. You can use any other sophisticated tools if available but never pluck the ICs with hand.

8. Soldering ICs without Using Sockets

It is not a good practice to solder an IC by hand. If it is soldered for a long time then the IC can get damaged due to overheat. So, first solder the IC socket and then insert the IC after the socket gets cooled. One more mistake that may happen is to solder the socket when the IC is inserted in the socket. If that is the case, then the socket solves no purpose. We need to solder the empty socket first and insert the IC after soldering. So, remember never to solder the IC directly on the circuit board, without using the socket.

So now that you must be having idea about the common mistakes, never forget to keep this in mind while preparing your own circuit board. Any other suggestion is welcome to be added.

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