Signal generator, which will be discussed, assembled only on one OS and two field-effect transistors. It can be successfully repeated, even novice radio Amateurs. The device generates rectangular voltage and triangular in shape frequency from 20 Hz to 20 kHz, as well as sawtooth oscillations of positive and negative polarity frequency from 40 Hz to 40 kHz.

The basis of the generator is the multivibrator OS, a simplified diagram of which is shown in figure. 1. Self-excitation multivibrator is provided by positive feedback through the divider R2R3, the period of oscillation is determined by the recharge time of the capacitor C1 through the resistor R1 to the level, given this divider, The output of op-amp are formed rectangular pulses with a duty cycle 2 (“meander”).

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Since the capacitor C1 is recharged through the resistor, it is formed varying according to the exponential law of voltage. To obtain high-linear triangular voltage instead of the resistor R1 is required to turn on bipolar current source, and for the formation of a triangular oscillation of the sawtooth voltage to provide the charging current, dozens of times more bit. All it is implemented in the function generator, a schematic diagram of which is presented in the text.

The generator consists of a multivibrator at the shelter DA1, adjustable bipolar current source for the transistor VT2 and the rectifier bridge VD1, and a source follower transistor VT1. The desired sub-band frequency select switch SA1, within the sub-band generator rebuild resistor R4, changing the bipolar current source. Switch SA3 choose the form of the generated oscillations (with the closure of its contacts, the frequency increases twice), and the switch SA2 — polarity sawtooth voltage. If the switch SA3 is set to, shown in the diagram, to the exit 1 supplied with a triangular voltage, and to the outputs 2 and 3 — rectangular (“meander”). When the closed contacts of this switch to the output 1 do sawtooth oscillations, and outputs 2 and 3 — short pulses, matching (time and duration) with their reverse swing. The maximum amplitude of the pulses at the output 1 — 0,5…2 In, the output 2 — 10 In (in the first case, the amplitude is controlled by resistor R3, the second resistor R6).

Instead of Oh К140УД6 in the generator can be applied К140УД7, К140УД8, instead of transistors KTZV — KSSB, КП307Е, build КПС104Б, КПС104Г, КПС104Д, and transistors КП103Е, КП103Ж, КП103И (if you use the latter the polarity of the bridge VD1 must be changed to return, and the output drain of the transistor VT1, and the upper circuit output resistor R3 to swap), Fixed resistors may be aircraft type or MLT, trimmer — SDR-1, SP5-2 or SP5-16, variables — SP or SPO. Oxide capacitors C4, C5 — C50-3, K50-6 or K53-1, C1, C6 — C50-6 or K53-7, the rest MBM or KM. Rectifier bridge VD1 and VD2 diodes, VD3 can be replaced by diodes series КД503, КД510, KD522 and t. p. The SA1 switch — RM or MPN-1; SA2, SA3 — P2K or МТ1.