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    „Introduction to Counters
    Like shift registers and other combinational circuits, there is another important element in digital electronics which we use most. They are counters. Counters are used not only for counting but also for measuring frequency and time ; increment memory addresses .

    Counters are specially designed synchronous sequential circuits, in which , the state of the counter is equal to the count held in the circuit by the flip flops. Counters calculate or note down the number that how many times an event occurred.

    Counters are the crucial hard ware components, and are defined as “The digital circuit which is used to count the number of pulses”. Counters are well known to us as “Timers”. Counter circuits are the best example for the flip flop applications. Counters are designed by grouping of flip flops and applying a single clock signal to them. In simple words, the counters are those, which have the group of storage elements like flip flops to hold the count.

    Counters have modes. The ‘mod’ of the counter represents the number of states of the cycles through it, before setting the counter to its initial state. For example, a binary mod 8 counter has 8 countable states. They are from 000 to 111. So the mod 8 counter counts from 0 to 7.

    Counting means incrementing or decrementing the values of an operator, with respect to its previous state value. So to perform the mathematical operation we use no devices other than counters. We cannot perform this action (counting) with any other logic devices rather than counters.

    The counters which use clock signal to change their transition are called “Synchronous counters”. This means the synchronous counters depends on their clock input to change state values. All flip flops in the synchronous counters are triggered by same clock signal.


    Their construction is very simple in design. All the flip flops are interconnected and will be driven by same clock signal.

    The state output of the previous flip flop determines the state change of the present flip flop.

    As all the flip flops will work synchronously, the synchronous counters don’t require settling.

    We require number of logic gates to implement the synchronous counters.

    Their operation is fast.

    Asynchronous counters

    Definition: The counters in which the change in transition doesn’t depend upon the clock signal input is known as “Asynchronous counters”. In these counters, the first flip flop is connected to the external clock signal, and the rest are clocked by the state outputs (Q & Q’) of the previous flip flop.


    Another name for Asynchronous counters is “Ripple counters”.

    These are very simple in design.

    As its design is simple, they use less number of logic gates to construct an asynchronous counter.

    Operation of asynchronous counters is very slow compared to synchronous counters.

    The DEA kept a huge database of people that purchased money counting machines
    Cutting corners: The DEA’s program to track Americans who bought money-counting machines ran from 2008 until 2013 and reportedly collected tens of thousands of records. An incorrectly redacted report shows how the agency hid the program from judicial oversight since they knew its legality was questionable.

    Money counters aren’t illegal and they are typically purchased by companies doing legitimate financial transactions. The DEA however worked under the assumption that if an individual wanted to purchase a machine, it was likely they were involved in money laundering or drug dealing. To try to catch these supposed criminals, the DEA issued wide ranging subpoenas to the manufacturers of such machines and collected the data in a database.

    A publicly released report by the Office of the Inspector General outlines the DEA’s use of such programs. Sections of the report are redacted, but a key section was mistakenly left uncensored. This inadvertent leak was first spotted by Twitter user Sarah St. Vincent.

    The DEA hid this information from the courts and others because they believed „”criminals would obtain money counters by other means if they knew that the DEA collected this data.”” The agents „”were instructed to state in reports […] that they received a lead from a source of information that indicated that the [suspect] may be involved in drug trafficking and money laundering.””

    In the report, all other mentions of „”money counters”” were supposed to be redacted but this paragraph was left in. The report goes on to describe field officers' complaints about how the program was generating too many false-positives to be a useful tool. The DEA later refined the program and was able to successfully make arrests and seize the illegal cash.

    The program was never subject to scrutiny by the courts because the DEA hid it from them. When the DEA wanted to act on a lead generated by the program, they would use Parallel Construction. This is a technique of first obtaining the information you want using questionable tactics, and then requesting a targeted subpoena to re-obtain it legally.

    The New York Times reached out to both the DEA and OIG but neither would comment.

    Count-by-weight Money Counting Machines outweigh friction counters
    Count-by-weight Money Counting Machines have come a long way since their introduction around 40 years ago.

    Flashback to 1979: After standing in line at the bank one day, Edgar Biss and other patrons patiently waited while the teller counted a pile of bills, lost count, and started over. As time ticked by and the line didn’t budge, Edgar thought, “There has to be a better, faster, more accurate way to count cash.” An engineer by trade, Edgar created the first count-by-weight Money Counting Machine – the Tellermate.

    Fast forward to today: Money Counting Machines are used worldwide in banks, convenience stores, casinos, quick-service restaurants, retail establishments, and other companies searching for ways to drive efficiency. Money scales reduce user error and improve accuracy. They calculate cash quickly and efficiently. They also drive adherence to process and free up employees’ time by streamlining a laborious procedure.

    The two most-popular types are count-by-weight devices and friction counters. We’ll get back to friction counters later, but first, let’s touch upon count-by-weight machines.

    Count-by-weight machines use a set of rules to count coins and batches of bills. Cash is stacked on a Money Counting Machine in bundles, rolls, cups or bags and is counted in seconds. The electronic device tracks each denomination to create a complete count of a cash drawer – in less than 60 seconds.

    Rather than weigh individual bills or coins, the Money Counting Machine assesses cash in batches and compares them against a stored average weight for each coin or bill, which it constantly updates. These intelligent cash counters know when one bill or coin is removed and adapt accordingly. Count-by-weight machines also adjust to variations that occur over time and still provide accurate counts. You see, a torn banknote weighs less than normal; while a bill covered with oil, dirt or humidity, is heavier. The device learns as it counts and makes adjustments to reflect weight differences. It’s that smart.

    How does a counterfeit detector pen work?
    ­I­f you have looked at the most recent $20 bills from the U.S. Bureau of Engraving and Printing, you know that they have an army of security features designed to make counterfeiting more difficult. The most obvious of these features is the „”20″” in the lower right corner written in color-change ink. There’s also a security strip embedded in the paper to the left of Andrew Jackson that is visible if you hold the bill up to the light. Other new features include micro-writing, a watermark and very closely spaced lines (for example, behind Jackson’s face) that are harder for a counterfeiter to reproduce.

    All of these features are nice, but no store clerk is going to stand and hold each $20 bill he or she receives up to the light to check for a security strip! It takes too long and it is not a flattering pose to strike.

    The counterfeit detector pen solves the biggest counterfeiting threat today. It used to be that a counterfeiting operation used expensive presses and special inks and papers to create exact duplicates of the bills. Today, the threat is much more mundane — people with color copiers and color printers try to create passable facsimiles of a bill. They are not trying to make an exact copy. They are trying to create something close enough that people won’t notice anything if they give the bill a passing glance. These folks are not particularly careful or meticulous, so they copy or print onto normal, wood-based paper.

    The counterfeit detector pen is extremely simple. It contains an iodine solution that reacts with the starch in wood-based paper to create a black stain. When the solution is applied to the fiber-based paper used in real bills, no discoloration occurs. The pen does nothing but detect bills printed on normal copier paper instead of the fine papers used by the U.S. Treasury.

    How to Exchange Coins for Cash With Minimal Fees
    Many people accumulate pocket change over time. That change finds its way into a coin jar or another container and builds up. One day, you’ll look at the container and realize that it’s accrued quite a bit of money and will want to do something with it.

    The catch, of course, is that a big pile of change is a hassle to deal with. Paying for a purchase with a mountain of coins is time-consuming and potentially annoying to the people around you. Some businesses will accept bulk change and convert it into dollars for you, but they charge a fee.

    Here are four ways to minimize or even eliminate the fees you may face for exchanging your coins for cash.

    Many banks and most credit unions offer a free conversion of coins to cash for account holders. They’ll simply dump your change into a sorting machine and give you cash after the change has run through it. Some banks offer this service with a small fee.

    If you find that your bank charges a fee for this, you might consider shopping around for a different bank or credit union.

    Many banks that won’t sort your coins for you will accept rolled coins, and some will even give you the empty paper rolls to do the coin rolling yourself. This does require you to sort the coins by hand, but then you’re able to deposit the coins for free.

    Another advantage of rolled coins is that you can often use them as cash for small purchases. A cashier may open the roll to examine the contents, but it’s an easy way to use large numbers of coins in stores for purchases.