Asynchronous Count-Down

The output of the circuit is a number in binary which is one lower than the input. For example , if both switches are closed (representing the number 3 in binary) the MSB will be a high signal (about 3.3 volts) and the LSB will be a low signal. This combination of signals can be described as the number two in binary. In other words, inputting a three to the circuit produces a two, inputing a two produces one, and inputing one produces zero. The circuit is asynchronous because there is no clock driving the circuit and because there is no feedback so the input is not dependent on the previous output. Instead the input values are set manually by opening and closing the switches.