Circuit Diagram Knowledge

The bench or table is the kingdom of a technician, hobbyist or electronics student. A Work benches must have at least an antistatic rubber surface, a good grounding system and a power strip with fuse protection. In case of sensitive equipment, the ideal is to work with a personal grounding straps, and even a little extra protection as an antistatic mat and grounded on the workbench surfaces, this protection prevents damage by static discharge.





Operation of electrical protection Bench

We can increment a counter with two simple circuits that will display its operation and how to build. One is the isolation transformer, which serves mainly to avoid electric shocks during construction or repair of circuits that are energized, such as switching power supplies, etc.. The other protection circuit bench is the lamp in series, a tool able to avoid further damage to electronic equipment. With just a light bulb in series with the AC mains and the circuit to be tested or repaired can avoid further damage in case of short circuit.

Isolation transformer easy and cheap

What is an isolation transformer

Isolation transformer as the name implies, isolates the mains of an appliance or power network, it depends on your usage. Various devices and old appliances, or even modern does not have transformer, they use a direct source, where coach or even curious how we run the risk of a shock, which in some cases can be fatal.





In Figure 2 we see a typical circuit power strip with an isolation transformer, the transformer primary is connected to AC mains that has a "live" phase and another phase neutral or earth (were not talking about the central ground pin ). This means that the mains 110 Volts AC (127 Volts) has a phase that is in the neutral or ground potential. The fatal crash occurs precisely for the reason that when you play barefoot or grounded the living phase of the network.





Already with the transformer T1 in its secondary, none of the terminals is grounded, if you accidentally touch one or other of the two wires of the secondary you will not receive shock. But if you touch both simultaneously you will receive a shock which can be fatal, but it is just touching the two at once.

Making our own isolation transformer

In Figure 1 we have a low cost circuit, this circuit uses two transformers, T1 and T2 are two common transformers, need not be equal, but must have the same tensions, the primary with the desired voltage, 110 volts, or both and the secondary 12 volt type 12v-0v-12v. The connection is simple, the secondary of T1 is connected to the secondary of T2. The chain should be at least 5 amps for a good performance.

The isolation transformer also keeps us away from equipment damage when were doing repairs on appliances, because it will have an AC output low. This does not prevent component damage, but it certainly will not help to have bigger problems.

Whats Lamp series , how it works and HOW ?

Since I can remember I use the protection system made ​​with lamp in series , this is an extremely simple tool , easy to make and extremely efficient. When using the lamp in series on a counter-top is possible to avoid serious accidents , further damage equipment , detect serious problems etc. . I always say that every technician and hobbyist must have a lamp standard on your counter-top .
Since the lamp works in series

We never know what is really happening when we have a device with the fuse blown input , can be an internal short circuit or blown fuse for a small outbreak that neither damaged the equipment. Replace the fuse and put the equipment in the electrical network can be risky , and would run the risk of having a new short - circuit, burns again the input fuse or worse.

Not to mention the equipment and appliances that do not have fuse, you would be taking a risk on these test equipment , without support , without protection for your wiring, it could even cause an explosion or fire . These times is that the use of a tool that had the ability to diagnose faults such as excessive consumption and short - circuit current limiting and not letting something more serious occurs with the equipment is necessary and indispensable on the bench .

It is precisely what the lamp in series makes it limits the electrical current ( according to the lamp power / watts ) , with all this we prevent current from passing to the unit , it will not have a blown fuse input and also we will not risk further damage the appliance , the power grid and safeguard the user of an explosion and fire .
How to make a lamp in series

The lamp in series bench if analyzed in a technical way , is a resistive load , we can easily replace the bulb wire resistors , but besides being more expensive , it has the advantage of a visual monitoring because the lamp increases brightness according to the increased consumption of the device under test . If the instrument is shorted visual indication will be the total brightness of the lamp . The resistive load does not affect the operation of the appliance , it means that he will usually work if connected in series with a lamp .




In Figure 3 we have a power strip circuit which uses a lamp in the series. The ideal is to have some lamps with different devices to test at least one of 40, 60, 100, 150 Watts power. There is no rule, but to test a device with less than 40 Watts consumption use the lamp 40 Watts or 60 Watts to test device with consumption of more than 40 Watts to 80 Watts lamps use 60 Watts and 100 Watts and consumption above 100 Watts 150 Watts use the lamp. But it has the technical decision in accordance with the terms of the apparatus and its use.

Using the Lamp series

The operating mode of the lamp in series is simple , lets assume that you have a sound system that has burned the fuse AC input , first lets replace that input fuse with another of equal value and connect equipment in lamp series.

If it is the case replace the lamp with an ideal power for the equipment . Surrounded by all the care and protection switch on the device , and make note of the brightness of the lamp .

The amount of glow will be important for the detection of the problem , if the lamp light with maximum brightness , surely remains short and the circuit should be checked more carefully . Components as the primary winding and secondary winding of the transformer , rectifier diodes , signs of overheating, smoke , components changed , jaded or leaking characteristics should be measured and analyzed .

To the extent that you are detecting problems , reconnect the appliance bulb in series . If the lamp brightness decrease , this is the time to connect the unit directly to the grid without the lamp in series .

But if the lamp does not light when the power is turned on , it is a sign that the short may have caused the burning of essential components for the source , as processor can have open or capacitors and integrated circuits oscillators in the case of switching power supplies .

Electrical protective circuit for Counter tops

In Figure 1 we have the complete scheme using the two protection circuits suggested, the lamp in series and the isolation transformer.

Attention!

Some equipment may not be connected in series lamp. These devices did not function smoothly even when used in series with the lamp. Article in All About the Lamp Usage in the Series Electronically you will find more information about the videos with lamps in series. In addition to a secure bench, safety rules will keep you away from the dangers of electricity, most accidents are preventable. Accidents do not happen without a cause, and most accidents are the result of not following operational security procedures. Read our disclaimer site.