Archive for tag: Voltmeter

FETVM-FET Voltmeter

Uncategorized | By: Diagram mania

This is a circuit of FETVM-FET Volmeter. The function of the VTVM is replaced by the FTEVM while at the same time ridding the usual line cord instrument. This circuit can allow a 0.5 volt scale range because drift rate of FETVM are superior to vacuum tube circuits. Here is the circuit: The 2N4340 are […]

DC, RMS, And Peak-to-Peak High Impedance Voltmeter

Uncategorized | By: Diagram mania

Analog meter normally doesn’t have high impedance since they don’t have buffer circuit inside. With active buffering, the input impedance of this circuit depends on the impedance of the op-amp. You can use other op-amp for higher impedance, but a low-cost 741 is enough for may application. The rectification inside the feedback loop path remove […]

Peak (Pulse) Voltmeter

Uncategorized | By: Diagram mania

This is a Peak Voltmeter circuit. This circuit can be viewed as a pulse stretcher, which catch fast pulse signal to be measured by a slow response voltmeter. Even a fast response meter need this circuit since our visual perception won’t be able to catch a fast event. Here is the schematic diagram of the […]

FET Buffered Analog Voltmeter

Uncategorized | By: Diagram mania

This is a voltmeter circuit that use FET as the buffer to improve the input impedance. This circuit uses A2N3819 FET which provides a solid-state VOM. Beside that, a cathode follower in a VOM of this circuit is The 2N3819. The calibration of this circuit is done by adjusting R12 (scale/sensitivity) and R14 (zero offset).  […]

LF356 4-Ranges Ac Millivoltmeter

Tester Circuits | By: Diagram mania

This is a 4-range AC millivolt meter circuit. This circuit is used to measure a AC voltage in millivolt range. This circuit has frequency response of a few Hz to about 50 kHz. The non-linearity of the rectifier circuit is eliminated by placing the rectifier inside the op amp feedback path. This circuit read the […]

Low-Drift High-Impedance JFET DC Voltmeter

Tester Circuits | By: Diagram mania

The voltmeter shown in the schematic diagram below has very high impedance. The range selector uses conventional voltage divider resistors, but since the following pre amplifier uses JFET, the divider can be designed using very high resistance series resistors. This DC voltmeter circuit also featured with low drift. This circuit uses a pair JFETs, which […]

Constructing Voltmeter Monitor Circuit using LM3914

Power Supply circuits | By: Diagram mania

With a few resistors, LEDs and using a LM3914 bar/dot display driver IC we can construct a simple 5V Voltmeter Monitor Circuit which provides TTL-compatible undervoltage and overvoltage warning signals. A complete circuit can be shown in the schematic below. This voltmeter monitor circuit is useful where quick and easy voltage adjustments must be made. […]

Voltmeter With LED For Car Battery

Battery and Charger Diagram | By: Diagram mania

Below is a comparator circuit which is can measure with step of 1 volt, the voltage of car battery. The indication of voltage is done by comparison of  battery voltage with the reference set by D1. This voltage is applied  to the inverting inputs of amplifiers with to compare the battery voltage. We can regulate […]