Digital frequency meters are the most widespread today. Their shortcoming is the insufficient presentation of measurements. If frequency changes, to understand in what party there is a change, it is possible not at once. The analog frequency meter though is less exact, but allows to define the sign of change of frequency instantly.
Instruction
1. Prepare any analog device capable to measure voltage from 0 to 1 V. It can be both the specialized voltmeter, and a multipurpose tester. Observe polarity at its connection. If in addition to analog indication nevertheless also digital is necessary for you, connect the digital multimeter working in measurementsconstanttension mode up to 2 V parallel to the device.
2. Take two diodes and include counter in parallel. An entrance signal if it has small amplitude, give on them via the resistor about a kilohm. Give the signal having bigger scope through the divider having the corresponding parameters. Remove the signal limited on amplitude from diodes. Now it does not bear information on amplitude any more - only about frequency. Consider that with an amplitude less than 0.5 V such limiter will not work.
3. Collect the one-vibrator of any design known to you. The K155AG1 one-vibrator is most convenient for analog frequency meters. 3, 4 and 7 these chips ground conclusions, and on a conclusion 5 give food (+5 V). 6 connect the voltmeter to a conclusion. Between plus of food and a conclusion 9 turn on the resistor (on several dozen kilohms), and between conclusions 10 and 11 - the condenser which capacity depends on measurement range. Give on an entrance (a conclusion 5) the reference signal with a frequency which is in the middle of range of measurement which is passed via the limiter and pick up the resistor and the condenser so that the arrow of the voltmeter was in the middle of a scale.
4. Now, giving the signals of different frequencies measured by a model frequency meter on an entrance make the table of correspondences of indications of the voltmeter to various frequencies. If two voltmeters are connected, consider that owing to features of a form of a signal of their indication can not coincide. Or establish the integrating chain, or make for them separate tables.
5. If you want to make a frequency meter multirange, pick up several pairs of resistors and condensers for different ranges. For a frequency meter which will measure frequency over one megahertz use a preliminary divider of frequency of any design. Arrange it between the limiter and the one-vibrator.