POWER ADAPTORS OR `PLUG PACKS`
Contents
1. connectors However the interchangeable plug system is safer and more elegant as the star plug system leaves the unused plugs exposed but still connected to the adaptor s output Fig any pieces of elect c equipment designed to operate from a DC power adaptor have the correct polarity indicated near the inlet socket asyshown at left The interchangeable plug system also allows you to obtain additional plugs to suit equipment with the more specialised types of power connector Jaycar Electronics can supply the special plugs necessary to use many of its adaptors with some of the Sony equipment for example Watch polarity With DC power adaptors there s another source a problems connector polarity Unfortunately there s no universal standard when it comes to the way electronic equipment designers wire up their DC power connectors some use the centre pin or plug ti the positive polarity while others use the outer or sleeve er adaptors which use the interchange the plugs are usually capable of being connecte the adaptor cable either way around This makes it Very easy to set the plug for the correct polarity However if you use an adaptor which only comes with a single fixed plug and its polarity turns out o be wrong for your equipment Murphy s Law strikes you ll probably have to cut the plug off the cable it another plug with the correct polarity So even when you find the co2. 3011 for CCD cameras 12V DC at 15 12 15 18V at 800mA Inline type MP 3034 12V DC at 450mA 12V DC at IA Inline type MP 3033 12V DC at IA 12V DC at IA Switchmode MP 3137 MP 3210 12V DC at 1 25A Switchmode MP 3220 f 12V DC at 2A Inline type MP 3017 12V DC at 4A Inline switchmode MP 3240 I5V DC at I 5A Switchmode MP 3423 18V DC at 1 2A Switchmode MP 3424 e type MP 3212 24V DC at IA Inline type MP 3037 e type MP 3018 24V DC at 2A Inline switch mode MP 3244 AC Adaptors Switchmode MP 3131 FV AC Phy ME 02 MP 3030 s 10V AC at IA MP 3025 3 12V DC at IA Switchmode MP 3130 ce ala eee 3 12V DC at 1 25A Switchmode MP 3031 j 32V DC at 5A Six o p voltages MP 3035 16V AC at 1 25A For home alarms MP 3021 3 13 8V at 2A Inline type MP 3036 17V AC at 1 25A For home alarms MP 3022 2x 11 5V AC at 1 25A Inline type MP 3055 For more information please refer to the latest Electus Distribution Catalogue or visit www electus distribution com au
3. Electus Distribution Reference Data Sheet PLUGPACK PDF 1 POWER ADAPTORS OR PLUG PACKS Power adaptors or plug packs are very handy devices providing a compact and convenient source of safe low voltage power derived from the mains Nowadays many small items of electronic equipment are designed to be operated from these adaptors either normally or as an alternative to batteries In most cases there s no problem using this kind of adaptor because equipment manufacturers usually either include a correctly matching adaptor with the equipment or make one readily available as an optional extra However problems can arise if you try to use a different adaptor perhaps because the correct one has become lost or damaged and they re no longer available While it s almost always possible to substitute a commonly available adaptor without upsetting the equipment s operation or causing any damage this does require considerable care and a good understanding of what you re doing There are a number of different types of adaptor and also plenty of potential traps for th unwary If you re not careful you can easily cause expensive damage to your equipment by connectin to either the wrong kind of adaptor or connectin the right kind but in the wrong way In this data sheet we ll try to give you the kn needed to avoid these problems so you can power adaptors with confidence and success Adaptor types The first thi
4. chaos There s another source of problems when you re trying to find a suitable power adaptor for a piece of electronic equipment the wide range of different low voltage power connectors in use These differ in terms of plug type internal and or external diameter insertion length and so on Atleast seven main types of power connector are in common use with quite a few other weird and wonderful types also used by some manufacturers of particular pieces of equipment such as personal CD and DVD players laptop computers camcorders and PDAs For example Sony is well known for the special sub miniature power connectors used on its equipment Most of these types of power connector are not compatible with each other which means that in order to use a power adaptor with a particular piece of equipment it needs to have the correct connector Which can pose problems Luckily many adaptors are supplied with either a multi way star plug on the end of the output cable Fig 5 or a range of interchangeable plugs Fig 6 Either approach generally allows you to use the right plug providing the equipment uses one of the more common Electus Distribution Reference Data Sheet PLUGPACK PDF 4 L l a r 3s N I om oS ene ae oT 2 5mm mini 3 5mm mini 1 3mm De 1 5mm De 2 1mm De 2 5mm De 2 1mm De The seven types of low voltage power input plug in most common use There are many others though
5. ltage for load currents lower tham the rated maximum For xample an adaptor rated to provide say 9V at up to 00mA might deliver IV when the load only draws 30mA and the voltage may rise even further to 14V or o if the load draws only 50mA In other words this type of adaptor is said to have poor voltage regulation This happens mainly because of the poor performance of the very small stepdown transformer they use and the modest filter capacitor As you might expect the wide variations in output voltage cam cause problems when you try to use this type of simplejadaptor with many pieces of electronic equipment For example equipment that doesn t draw much current might overheat or even be damaged because ofsthe higher voltage that the adaptor applies to it at that lower current level Or if the current drawn by the equipment tends to vary up and down in operation which happens with many radios and amplifiers for example the resulting variations in the adaptor s output de circuitry to lated DC as this an the traditional ectifier allowing ter in weights deliver higher o approach is more efi stepdown transformer a them to be smaller and li Clearly then it s important to pick the correct type of adaptor for your application Picking the wrong one could be disastrous so we ll now look more closely at each of the various types Fig l The cheapest DC power adaptors are the unregulated type wi
6. n personal computers Here the mains AC voltage is rectified directly to produce high voltage DC which is then used to power a very efficient high frequency DC DC converter Fig 3 This runs at 200kHz or so and uses a very small and light stepdown transformer Negative feedback is used to regulate the output voltage Because of its much higher efficiency this type of adaptor tends to be noticeably smaller and lighter than the analog regulated type for the same output rating Most adaptors used to power laptop and portable computers are of the switch mode type in order to deliver a regulated output voltage at relatively high currents For many applications there s no practical difference between the two types of regulated adaptor apart from the smaller size and weight of the switch mode type They both deliver an output voltage that s reliably constant over a wide current range so simply picki one with the right output voltage to suit your equipment and its current drain will almost always trouble free eration Transformer Low voltage AC output oblem because the m them almost always includes an AC adaptor issaccidentally of equipment designedsto run from n cause considerable damage So adaptors but they re really a small battery charger in the sam type of compact case In Incidentally regulated adaptors are available in both fixed voltage and selectable voltage versions just like
7. ng to be aware of is that t few different types of adaptor For exa low voltage DC direct current like a deliver low voltage AC alternating cu quite different of course Even among those which deliver DC few different types There are output voltage is unregulated al wide range depending upon ho have to deliver Then there s t regulated type where the o constant even when the lo range There s also special not to power electronic equipm of power hen re deliver quite low DC adaptors As mentioned earlier the most common type of adaptor is designed to deliver low voltage DC as this is adaptor mer plus a Fig l The transformer ge down to a much lower r and capacitor convert the generally available with either ut voltage i e 6V 9V 10V 12Veor h to select one of a number of also made in a rangesof sizes ent levels of maximum output there are nominal 9V adaptors nt ratings of 1 00mA 200mA 300mA ilarly there are selectable voltage adaptors w he maximum urrent is fixed at say 300mA but the nominal output voltage can be set to any of six values between 3V and 12V The main problem with this simple type of DC or is that the actual output voltage tends to vary irly wide range for different levels of current fad to the load i e your radio CD player PDA or whateyer In particular the output voltage tends to rise significantly above the adaptor s nominal vo
8. regulated adaptors are more suitable for powering any equipment which is relatively critical of its supply voltages That s because additional circuitry inside this type of adaptor regulates or stabilises the output voltage holding it very close to the nominal value even when the load current varies over a wide range So a regulated 9V IA adaptor will deliver an output voltage of almost exactly 9V whether the load draws a current as lows 30mA or as high as IA There are actually two types of regulated DC adaptor Onestype is essentially the same basic transformer and rectifierycircuit as in a simple unregulated supply but with additional analog circuitry at the output to regulate the output voltage Often this is via a fixed or adjustable Switching Converter Control Circuit Feedback for regulation Ill High voltage switching FETs Regulated DC output Hl High Frequency Transformer Fig 3 What s inside the switch mode type of regulated DC power adaptor The mains AC is rectified to produce high voltage DC which is then fed to a very efficient switching DC DC converter Feedback allows the converter to monitor and regulate its output voltage Electus Distribution Reference Data Sheet PLUGPACK PDF 3 three terminal regulator IC as shown in Fig 2 The other type of regulated supply is the switch mode type which is essentially a small version of the switch mode power supply used in moder
9. rrect DC po a piece of equipment it s still important to that it s connected to the adaptor output c correct polarity Connecting the DC power fo the equipment the wrong way around will generally stop it Note that polarity normally isn t a problem with AC from working and could easily cause ex adaptors because their output isn t polarised anyway In How do you find the correct polari i fact some AC adaptors are not supplied with an output marked on the equipment case alon plug at all just bared wires on the end of the lead connector Fig 7 Failing this you in the equipment s user manual In may have to open the equipment an connections with a multimeter or DM find it specified eme cases you Copyright Electus Distribution 2001 A very wide range of DC p adaptors are stocked by Electus Distribution stores and authorised dealers All are approved f me complete with seven interchangeable output plugs to make it easy for you to select the correct uick rundown on the range available and their catalogue numbers Unregulated DC Adapt 5V DC at 2A Inline switch mode MP 3230 9V DC at 150mA 5VeDC at 2 5A Switchmode MP 3140 9V DC at 500mA 6V DOCjat 1 66A Inline switch mode MP 3232 9V DC at 850mA MP 3009 6V DC at 2A Switchmode MP 3141 9V DC at IA MP 3008 9V DC at lA Switchmode MP 3136 10V DC at 850mA 9 24V DC at 5 IA Switchmode MP 3420 IOV DC at l 12V D at 300mA MP
10. th only a transformer rectifier and filter But their poor output regulation can cause problems 240V plug pins Transformer D1 4 reer Unregulated DC output Electus Distribution Reference Data Sheet PLUGPACK PDF 2 D1 4 Transformer 240V plug pins output voltage has a range of in unregulated type but has lin constant A small switch may be a Regulator Regulated DC output adaptor is similar to the simple lator IC added to keep the output o allow selectionjof different d at left The unit pictured also lugs to suit different equipment voltage might easily produce distortion or ot effects such as varying hum level If your equipment does draw a fairly stea it s still possible to use this type of simple adaptor with it by carefully checking the equi load current with its correct supply voltage and then selecting an adaptor which does produ he right voltage at that current level Needless to say this can involve a testing and experimenting For exa of equipment which draws only as its actual output voltage ris drain Or a similar adjustabl nominal output set to 6V Of course you may not experimenting or may equipment s current dr enough because its voltage will inevitably vary too widely In these cases you ll need to use the regulated e of adaptor ulated adaptors Theyre more complex inside and hence more expensive but
11. the simpler unregulated type In this case the voltage figures aren t just nominal values though they re the actual voltages you get so there s usually no need for any measurement or experimenting Another point about regulated adaptors of both types is that their DC output tends to be smoother than that from unregulated adaptors ous limitations many cases they re still based on a simple st pdown transformer and rectifier combination but there may be additional circuitry to vary the output current level depending on the terminal voltage of the battery they re designed to charge Because of the way their voltage current performance is optimised for charging particular kinds of battery this type of adaptor is generally quite unsuitable for powering equipment directly The AC type of power adaptor is q any of the DC types That s because this essentially just an AC stepdown transforme nly suitable e alarm systems or as are some Fig 6 Most moder adaptors come with of interchangeable output plugs which is a somewhat better way to provide the necessary flexibility They re safer and also allow you to choose the right polarity Charger adaptors designed to suit specialised types of battery such as the lithium ion type can be quite expensive because they include microcomputer based circuitry to control charging current levels Connector
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