The LF1 LFP1 and LFM4 form a range of oscillators providing sine and square waves from 10Hz to 1MHz with an output of up to 12V pk-pk. Frequency is continuously variable over five decade ranges by a rotary control with range changes accomplished by push button switching. Output amplitude is continuously variable between four switched ranges with maximum outputs of 12mV pk-pk; 120mV pk-pk; 1.2V pk-pk and 12V pk-pk. The scale around the 'Fine Amplitude1 control of the LF1 and LFP1 provides an indication of output amplitude and in the case of the LFM^ the output is monitored by a meter scaled in volts pk-pk and dBm. The 'Common' output terminal is bonded electrically to the chassis and in turn to the mains earth. For greater frequency accuracy and stability a reference signal may be coupled to the 'sync.1 socket. The sine wave output of this socket may also be used to trigger ancillary equipment such as an Oscilloscope The LFM^i offers the additional facilities of TTL output when operating on square wave, and operation from internal batteries as well as mains. The LFP1 is the power version of the LF1 and offers all the facilities of this model plus a power Amplifier capable of delivering up to 3 watts into a 3Ω load over the audio bandwidth of 25Hz to 20kHz. The instrument is normally supplied wired for operation from 150V to 260V 50/60Hz inputs. With the exception of the LFP1 this operating voltage may be changed to 95-130V by an internal wiring change. A mains 'ON' neon indicator is located on the front panel.