Wiring Material: meter

Showing posts with label meter. Show all posts

Thursday, September 25, 2014

Accurate Capacitance Meter Circuit Diagram

The charges on Cr and CX are now equal and the meter indicates by how much the voltage across CX differs from that across Cy. Buffer IC3 presents a very high load impedance to CX.

This relies on the formula C = O/V where C is the capacitance in Farads, O is the charge in Coulombs and V is the voltage in volts. lf therefore two capacitances have equal charges, their values can be calculated when the voltages across them are known.
Each time the output of gate N2 rises, the charges of capacitors C2 and C3 are transferred to Cr and CX by trensistors Tl and T3 respectively.
For instance, to enable a capacitor of 470 pF to be measured, C2 and C3 have to be 10. . . 20 pF.
The circuit is reasonably accurate for values of CX up to 100 uF:
Two circuits ensure that reference capacitor Cr and the capacitor to be measured, CX, are charged equally. The circuit for Cr consists of C2, D1 and T1 and that for CX of C3, D2 and T3.
ln this capacitance meter, the value of a capacitor is determined by giving it the same charge as a refer- ence capacitance and then comparing the voltages across them.
The voltage across Cr is compared by lC2 with a reference voltage derived from the power supply via R3/R4. When the voltage across Cr ‘ exceeds the reference voltage, com- parator IC2 inverts which inhibits N2 and causes N3 to light LED D3.
When the output of N2 drops, C2 and C3 recharge via diodes D1 and D2. Gate N2 is controlled by astable multivibrator N 1 which operates at a frequency of about 2 kl-lz: Cr and CX are therefore charged at that frequency.
Above that value the y measurement will be affected by leakage currents. To measure capacitors of up to 100 pF, the values of C2 and C3 should be increased to 1 AF. c l Current consumption is minimal so that a 9 V battery is an adequate power supply.
Pressing reset button S1 causes both Cr and CX to discharge via T2 and T4 respectively, after which the charging process restarts and the circuit is ready for the next measurement. The meter is calibrated by using two identical 10 nF capacitors for Cr and CX. Press the reset button and, when the LED lights, adjust preset P1 to give a meter reading of exactly one tenth of full scale deflection (fsd). That reading corresponds to 1 x Cr.
lf, therefore, Cr = 100 nF and CX = 470 nF, the meter will read 0.47 of fsd. To ensure a sufficient number of charging cycles during a measure· ment, Cr and CX-should not be smaller than 4.7nF. To measure l smaller values, capacitors C2 and C3 will have to be reduced.

Friday, August 29, 2014

Simple Panel Frequency Meter Wiring diagram Schematic

This is a Simple Panel Frequency Meter Circuit Diagram to measure the frequency of 230V AC mains. When you connect it to the 230V AC line, the display shows the line frequency. Generally, the line frequency is 50 Hz, which may vary from 48 Hz to 52 Hz. Beyond this frequency range, sensitive equipment may start malfunctioning.

The AC mains supply is stepped down by transformer X1 to deliver a secondary output of 9V-0-9V AC, 250 mA. The secondary output of the transformer is rectified by diodes D1 and D2, filtered by capacitor C1 and given to regulator IC1 to produce regulated 6V DC. 9V AC is also connected to pins 2 and 6 of IC2 via resistor R1. Timer IC2 converts the sinewave frequency sample of AC mains into a square wave that is more suitable for the schema operation.

Simple Panel Frequency Meter Circuit Diagram

Fig. 1: The schema of the panel frequency meter

IC CD4093 (IC3) is used as an oscillator-cum-divider. The oscillator, wired around gate N1, produces 10Hz clock. Decade counter IC4 divides 10Hz clock by 10 to produce 1Hz clock. The output of gate N1 is fed back to its inputs via potentiometer VR1 and resistor R4. Capacitor C2 connected between the inputs of gate N1 and ground charges/discharges depending on the logic level at the output of gate N1. The values of VR1, R4 and C2 are selected to produce accurate 10Hz clock.

Decade counter IC CD4017 (IC4) divides the output of IC3 by 10 to provide one pulse per second. LED1 connected to pin 12 of IC4 gives one flash per second to indicate that the oscillator and the counter are working properly.

Fig. 2: Top and bottom views of LTS543 common-cathode, 7-segment displays

This 1Hz clock is fed to clock pin 14 of decade counter IC CD4017 (IC5), whose Q0 output is given to pin 2 and the square wave produced by IC2 is given to pin 1 of AND gate N1. Therefore, the unknown frequency of AC mains line, applied to pin 1 of AND gate N1, passes through it for only one second and the number of clocks per second are counted by IC7 and IC8.

Decade counters/7-segment decoders IC7 and IC8 are cascaded to drive common-cathode, 7-segment displays DIS1 and DIS2 (each LTS543). DIS1 shows units place of the frequency and DIS2 shows tens place. The top and bottom views of LTS543 common-cathode, 7-segment displays are shown in Fig. 2.

This is an auto-reset schema. You can select the reset time of 1 second through 5 seconds using rotary switch S2, which is connected to reset pins of IC5, IC7 and IC8. For long-time display of the frequency, keep the knob of rotary switch S2 towards fifth position. Keeping rotary switch S2 to first position (minimum reset time) allows you to instantly see any variation in the supply frequency on the display. Also, while adjusting the generator frequency to mains frequency, keep rotary switch S2 towards first position.

Author: V. David Sourced By: EFY

Tuesday, August 19, 2014

Frequency Meter for AC line Wiring diagram Schematic

There are specific gauges are of little use for most areas of electronics, but some are expensive and hard to find even Brazil. An example is the frequency meter AC line, it really is a measuring instrument of little or no use to most of us. We can use a frequency common adapting a cable, but for anyone working with inverters, UPS and generators, this is a primary tool.

Frequency Meter for AC line Circuit Diagram

Here a schema meter AC line frequency super simple and easy construction that can measure the frequency of 10Hz to 100Hz at a voltage of 110 V to 240 V.
This schema converts the sine wave output of the square wave 100k watt resistor and zener diode 1 watt 6.8V which may be a 1N3829A.

The medium is directly proportional to frequency, so it can be read in a 100mA ammeter (M1).
To calibrate the use of 60Hz known home network, set the pot VR1 to read 60mA.