## Measurement

1. Inductance meter circuit.

2. Inductance meter based on 7000 logic gates.

3. Capacitance meter with one-shot 74121.

4. Inductance meter circuit as add-on for frequency counter.

5. Capacitance meter based on 7400 logic gates.

6. Capacitance meter uses 7400 logic gates and 3x7490 binary counters.

7. Inductance / capacitance meter .

8. Antenna current meter.

9. Sensitive millivoltmeter.

10. L, C meter based on IC 4000 series.

11. L, C meter based on IC 7400 series.

12. HF rectifier voltmeter.

13. Capacitance meter based on 7400 logic gates.

14. AC voltmeter with linear scale.

15. X-ray - photometer.

It uses cadmium-sulfide photoresistor as X-ray sensor.

16. Nonlinear double T-shaped bridge.

17. AC voltmeter with linear scale.

18. How to measure impedance of antenna.

1. Set the signal-generator to measurement frequency, and set the switch **S** to the **"1"** position.

2. Set the antenna for the same frequency by the variable inductance **L** until the ammeter **A** displays the maximum current **I**_{m}.

3. Then set the switch to the **"2"** position, and with the variable capacitor ** C** get the maximum value of the ammeter **A**.

4. Now adjust the potentiometer **R** until the ammeter **A** displays the maximum current **I**_{m} again.

Value of **R** in this position is equal to the impedance of antenna **R**_{r} at the measurement frequency. Radiated power of antenna is:

**P**_{r} = I_{m}^{2} x R_{r}

19. Add-on for frequency counter for inductance measurement.