| Speaking of Analog computation: A single artificial neuron could be implemented as: Weighted Sum Using a summing amplifier: net = Σ_i (Rf/Ri * xi) Where resistor ratios set the synaptic weights. Activation Function Common op-amp activation circuits: Saturating function: via op-amp with clipping diodes → approximated sigmoid Hard limiter: comparator behavior for step activation Tanh-like response: differential pair circuits Learning Early analog systems often lacked on-device learning; weights were manually set with potentiometers or stored using: Memristive elements (recent) Floating-gate MOSFETs Programmable resistor networks |