An electrical synapse is a mechanical and electrically conductive link between two abutting neuron

Neuron

A neuron is an electrically excitable cell that processes and transmits information by electrical and chemical signaling. Chemical signaling occurs via synapses, specialized connections with other cells. Neurons connect to each other to form networks. Neurons are the core components of the nervous...

s that is formed at a narrow gap between the pre- and postsynaptic neurons known as a gap junction

Gap junction

A gap junction or nexus is a specialized intercellular connection between a multitude of animal cell-types. It directly connects the cytoplasm of two cells, which allows various molecules and ions to pass freely between cells....

. At gap junctions, such cells approach within about 3.5 nm of each other, a much shorter distance than the 20 to 40 nm distance that separates cells at chemical synapse

Chemical synapse

Chemical synapses are specialized junctions through which neurons signal to each other and to non-neuronal cells such as those in muscles or glands. Chemical synapses allow neurons to form circuits within the central nervous system. They are crucial to the biological computations that underlie...

. In organisms, electrical synapse-based systems co-exist with chemical synapses.

Compared to chemical synapse

Chemical synapse

Chemical synapses are specialized junctions through which neurons signal to each other and to non-neuronal cells such as those in muscles or glands. Chemical synapses allow neurons to form circuits within the central nervous system. They are crucial to the biological computations that underlie...

s, electrical synapses conduct nerve impulses faster, but unlike chemical synapses they do not have gain

Gain

In electronics, gain is a measure of the ability of a circuit to increase the power or amplitude of a signal from the input to the output. It is usually defined as the mean ratio of the signal output of a system to the signal input of the same system. It may also be defined on a logarithmic scale,...

 (the signal in the postsynaptic neuron is the same or smaller than that of the originating neuron).