The “London” Operational Amplifier has input devices such as an LDR, microphone input, 100kΩ potentiometer and 1µF capacitor. There are six resistors with space for an additional component. An offset control is included, plus a 1A power amplifier for loads eg. a loudspeaker, motor or lamp. A Wein network is included. Output can be fed through the power amplifier into a loudspeaker.