A trigger is the simplest device, which is a digital machine. It has two states of stability. One of them is assigned the value “1”, and the other - “0”. The state of the trigger, as well as the value of the binary information that is stored in it, is determined by the output signals: direct and inverse. If the direct output has a potential corresponding to a logical unit, then such a trigger state is called single (in this case, the signal level at the inverse output corresponds to a logical zero). If there is no potential, then such a device status is called zero.
Types of Triggers Classification
- By the method of the recorded information, asynchronous and synchronous triggers are distinguished. In asynchronous devices, switching occurs when information signals arrive at the inputs. In synchronous ones, in addition to the main information ones, there are control inputs (one or several). Such triggers switch when control signals arrive at them.
- According to the method of information management, devices are divided into statistical, dynamic, single-stage and multi-stage. The principle of operation of the trigger in statistical control is to switch the device due to the level of the signal supplied to the information inputs, in dynamic control - to change the potentials supplied to the inputs of the semiconductor device. Single-stage devices have one control stage, two-stage devices have two. Triggers of synchronous type with one-stage storage of information are called single-cycle, respectively, with two-stage recording - push-pull.
- JK-trigger, RS-triggers, T-trigger, D-trigger, and other types of devices are distinguished by the type of implementation of logical connections.
The main parameters of all types of triggers are the maximum duration of the input signal, the delay time required to switch the device, and also allowing the response time.
Trigger Input Type Designations
- R - means a separate input to set the device to zero.
- S - switching the device to single mode.
- K is the input of the divided installation of the universal trigger in the zero position.
- J - means separate switching of the semiconductor device to a single state.
- T is the counting input of the device.
- D - trigger switching input to the mode that repeats the input level.
- C is the synchronizing input of the device.
- V - control, allowing entry.
The main types of triggers
- Asynchronous RS trigger. This device has two stable states and two inputs - R and S.
- T-trigger is the most popular type of semiconductor devices, it has only one information (T) input, it is also called countable. The synchronous RS-trigger has an additional control (C) input.
- D trigger Devices of this type also have one information (D) input and represent a time delay.
- A DV trigger is essentially the same D trigger, but with an additional (V) control input.
- JK trigger. This type of device differs from asynchronous devices in that when the value of the combinations prohibited for the device is RS-type, they invert the stored information.