Gigaohmvoltmeter - Revision history

Thomastheo: /* Why? */

2017-12-24T10:50:42Z

Why?

← Older revision		Revision as of 10:50, 24 December 2017
Line 25:		Line 25:
	==Why?==		==Why?==

	It's very useful for measuring DC voltages without having to worry about loading down the circuit under test. The input impedance of a regular multimeter can sometimes be too much of a burden for circuits incapable of delivering sufficient current to maintain voltage while taking a reading. Thanks to the gigaohm input impedance, this meter draws only 1 nanoamp per volt of deflection. I built it to measure the output of the feeble high voltage supplies generally used for geiger counters and photomultipliers.		It's very useful for measuring DC voltages without having to worry about loading down the circuit under test. The input impedance of a regular multimeter can sometimes be too much of a burden for circuits incapable of delivering sufficient current to maintain voltage while taking a reading. Thanks to the gigaohm input impedance this meter draws only 1 nanoamp per volt of deflection. I built it to measure the output of the feeble high voltage supplies generally used for geiger counters and photomultipliers.

	==It doesn't work==		==It doesn't work==

	Put it on my Samla (thomas), and let me know. Thanks!		Put it on my Samla (thomas), and let me know. Thanks!

Thomastheo: /* Why? */

2017-12-24T10:49:46Z

Why?

← Older revision		Revision as of 10:49, 24 December 2017
Line 25:		Line 25:
	==Why?==		==Why?==

	It's very useful for measuring DC voltages without having to worry about loading down the circuit under test. The input impedance of a regular multimeter can sometimes be too much of a burden for circuits incapable of delivering sufficient current to maintain voltage while taking a reading. Thanks to the gigaohm input impedance, this meter draws only 1 nanoamp per volt of 'deflection'. I built it to measure the output of the feeble high voltage supplies generally used for geiger counters and photomultipliers.		It's very useful for measuring DC voltages without having to worry about loading down the circuit under test. The input impedance of a regular multimeter can sometimes be too much of a burden for circuits incapable of delivering sufficient current to maintain voltage while taking a reading. Thanks to the gigaohm input impedance, this meter draws only 1 nanoamp per volt of deflection. I built it to measure the output of the feeble high voltage supplies generally used for geiger counters and photomultipliers.

	==It doesn't work==		==It doesn't work==

	Put it on my Samla (thomas), and let me know. Thanks!		Put it on my Samla (thomas), and let me know. Thanks!

Thomastheo at 10:48, 24 December 2017

2017-12-24T10:48:51Z

← Older revision		Revision as of 10:48, 24 December 2017
Line 11:		Line 11:
	This meter is '''only''' designed to be used for measuring '''very low current''' moderate to high voltage supplies. There is no input protection whatsoever other than the gigaohm resistor, which is rated for a maximum of 1500VDC. The banana jacks are not meant for high-voltage high-current applications. The isolation is not adequate for safe operation with power supplies capable of delivering anything more than a tickle's worth of current.		This meter is '''only''' designed to be used for measuring '''very low current''' moderate to high voltage supplies. There is no input protection whatsoever other than the gigaohm resistor, which is rated for a maximum of 1500VDC. The banana jacks are not meant for high-voltage high-current applications. The isolation is not adequate for safe operation with power supplies capable of delivering anything more than a tickle's worth of current.

	==What's in the box==		==Operating instructions==

			Connect circuit to meter with banana jacks. Turn on meter. Cross fingers. Multiply reading by 10 for actual voltage value. Keep in mind that the banana jacks (and cables) are most likely not rated for the voltages you are using them at, so suspend them off and away from conductive surfaces. Keep in mind that this is a high impedance device, and that whatever you are connecting it to is most likely also a high impedance circuit; Long cables can couple in a lot of noise. To minimize this problem I cobbled together a pair of really short banana-crocodile cables.

			==What's in the box?==

	This is nothing more than a resistive divider and a high impedance voltmeter. The divider consists of a Dale 1 gigaohm 1.5kv 1% tolerance resistor, and a regular anonymous 100K carbon resistor. Crashjuh supplied a Dynatek 200 millivolt 200 megaohm input impedance panel meter, which is connected across the 100k resistor. Because of the 200mV range, the reading shown on the display ''does'' need to be multiplied by 10x.		This is nothing more than a resistive divider and a high impedance voltmeter. The divider consists of a Dale 1 gigaohm 1.5kv 1% tolerance resistor, and a regular anonymous 100K carbon resistor. Crashjuh supplied a Dynatek 200 millivolt 200 megaohm input impedance panel meter, which is connected across the 100k resistor. Because of the 200mV range, the reading shown on the display ''does'' need to be multiplied by 10x.
Line 19:		Line 23:
	</gallery>		</gallery>

	~~==Operating instructions==~~		==Why?==

	Connect circuit to meter with banana jacks. Turn on meter. Cross fingers. Multiply reading by 10 for actual voltage value. Keep in mind that the banana jacks (and cables) are most likely not rated for the voltages you are using them at, so suspend them off and away from conductive surfaces. Keep in mind that this is a high impedance device, and that whatever you are connecting it to is most likely also a high impedance circuit; Long cables can couple in a lot of noise. To minimize this problem I cobbled together a pair of really short banana-crocodile cables.

	==Why==

	This voltmeter is useful for measuring DC voltages without loading down the circuit under test. The input impedance of a regular multimeter can sometimes be too much of a burden for circuits incapable of delivering sufficient current to maintain voltage while taking a reading. Thanks to the gigaohm input impedance, this meter draws only 1 nanoamp per volt from the circuit under test. That is sufficiently low to allow measurement of voltage across a geiger tube while it is operating, which happens to be the primary reason for building the thing in the first place.

	~~==Can I open it~~?==

	No. ~~There is~~ a gigaohm ~~resistor inside~~, ~~and it does not like finger grease, Mate spray, or sideways glances~~. ~~The battery should last forever, provided you turn~~ it ~~off after use~~.		It's very useful for measuring DC voltages without having to worry about loading down the circuit under test. The input impedance of a regular multimeter can sometimes be too much of a burden for circuits incapable of delivering sufficient current to maintain voltage while taking a reading. Thanks to the gigaohm input impedance, this meter draws only 1 nanoamp per volt of 'deflection'. I built it to measure the output of the feeble high voltage supplies generally used for geiger counters and photomultipliers.

	==It doesn't work==		==It doesn't work==

	Put it on my Samla (thomas), and let me know. Thanks!		Put it on my Samla (thomas), and let me know. Thanks!

Thomastheo: /* What's in the box */

2017-12-24T10:30:50Z

What's in the box

← Older revision		Revision as of 10:30, 24 December 2017
Line 14:		Line 14:

	This is nothing more than a resistive divider and a high impedance voltmeter. The divider consists of a Dale 1 gigaohm 1.5kv 1% tolerance resistor, and a regular anonymous 100K carbon resistor. Crashjuh supplied a Dynatek 200 millivolt 200 megaohm input impedance panel meter, which is connected across the 100k resistor. Because of the 200mV range, the reading shown on the display ''does'' need to be multiplied by 10x.		This is nothing more than a resistive divider and a high impedance voltmeter. The divider consists of a Dale 1 gigaohm 1.5kv 1% tolerance resistor, and a regular anonymous 100K carbon resistor. Crashjuh supplied a Dynatek 200 millivolt 200 megaohm input impedance panel meter, which is connected across the 100k resistor. Because of the 200mV range, the reading shown on the display ''does'' need to be multiplied by 10x.

			<gallery>
			File:Voltmeterinside.jpg\|That's all, folks.
			</gallery>

	==Operating instructions==		==Operating instructions==

Thomastheo: /* Operating instructions */

2017-12-21T19:49:46Z

Operating instructions

← Older revision		Revision as of 19:49, 21 December 2017
Line 17:		Line 17:
	==Operating instructions==		==Operating instructions==

	Connect circuit to meter with banana jacks. Turn on meter. Cross fingers. Multiply reading by 10 for actual voltage value. Keep in mind that the banana jacks (and cables) are most likely not rated for the voltages you are using them at, so suspend them off and away from conductive surfaces. Keep in mind that this is a high impedance device, and that whatever you are connecting it to is most likely also a high impedance circuit; Long cables can couple in a lot of noise. To minimize this problem I cobbled together a ~~couple~~ of really short banana-crocodile cables.		Connect circuit to meter with banana jacks. Turn on meter. Cross fingers. Multiply reading by 10 for actual voltage value. Keep in mind that the banana jacks (and cables) are most likely not rated for the voltages you are using them at, so suspend them off and away from conductive surfaces. Keep in mind that this is a high impedance device, and that whatever you are connecting it to is most likely also a high impedance circuit; Long cables can couple in a lot of noise. To minimize this problem I cobbled together a pair of really short banana-crocodile cables.

	==Why==		==Why==

Thomastheo at 19:49, 21 December 2017

2017-12-21T19:49:06Z

← Older revision		Revision as of 19:49, 21 December 2017
Line 13:		Line 13:
	==What's in the box==		==What's in the box==

	This is nothing more than a resistive divider and a high impedance voltmeter. The divider consists of a Dale 1 gigaohm 1.5kv 1% tolerance resistor, and a regular anonymous 100K carbon resistor. Crashjuh supplied a Dynatek 200 millivolt 200 megaohm input impedance panel meter, which is connected across the 100k resistor. Because of the 200mV range, the reading shown on the display ''does'' need to be multiplied by 10x.wo		This is nothing more than a resistive divider and a high impedance voltmeter. The divider consists of a Dale 1 gigaohm 1.5kv 1% tolerance resistor, and a regular anonymous 100K carbon resistor. Crashjuh supplied a Dynatek 200 millivolt 200 megaohm input impedance panel meter, which is connected across the 100k resistor. Because of the 200mV range, the reading shown on the display ''does'' need to be multiplied by 10x.

	==Operating instructions==		==Operating instructions==

	Connect circuit to meter with banana jacks. Turn on meter. Cross fingers. Keep in mind that the banana jacks (and cables) are most likely not rated for the voltages you are using them at, so suspend them off and away from conductive surfaces. Keep in mind that this is a high impedance device, and that whatever you are connecting it to is most likely also a high impedance circuit; Long cables can couple in a lot of noise. To minimize this problem I cobbled together a couple of really short banana-crocodile cables.		Connect circuit to meter with banana jacks. Turn on meter. Cross fingers. Multiply reading by 10 for actual voltage value. Keep in mind that the banana jacks (and cables) are most likely not rated for the voltages you are using them at, so suspend them off and away from conductive surfaces. Keep in mind that this is a high impedance device, and that whatever you are connecting it to is most likely also a high impedance circuit; Long cables can couple in a lot of noise. To minimize this problem I cobbled together a couple of really short banana-crocodile cables.

	==Why==		==Why==

Thomastheo: /* What's in the box */

2017-12-21T13:35:36Z

What's in the box

← Older revision		Revision as of 13:35, 21 December 2017
Line 13:		Line 13:
	==What's in the box==		==What's in the box==

	This is nothing more than a resistive divider and a high impedance voltmeter. The divider consists of a Dale 1 gigaohm 1.5kv 1% tolerance resistor, and a regular anonymous 100K carbon resistor. Crashjuh supplied a Dynatek 200 millivolt 200 megaohm input impedance panel meter, which is connected across the 100k resistor. Because of the 200mV range, the reading ~~output by~~ the display ''does'' need to be multiplied by 10x.wo		This is nothing more than a resistive divider and a high impedance voltmeter. The divider consists of a Dale 1 gigaohm 1.5kv 1% tolerance resistor, and a regular anonymous 100K carbon resistor. Crashjuh supplied a Dynatek 200 millivolt 200 megaohm input impedance panel meter, which is connected across the 100k resistor. Because of the 200mV range, the reading shown on the display ''does'' need to be multiplied by 10x.wo

	==Operating instructions==		==Operating instructions==

Thomastheo: /* Why */

2017-12-21T11:56:55Z

Why

← Older revision		Revision as of 11:56, 21 December 2017
Line 21:		Line 21:
	==Why==		==Why==

	This voltmeter is useful for measuring DC voltages without loading down the circuit under test. The input impedance of a regular multimeter can sometimes be too much of a burden for circuits incapable of delivering sufficient current to maintain voltage while taking a reading. ~~By using a voltage divider with ridiculous values of 1~~ gigaohm, ~~the~~ meter draws only 1 nanoamp per volt from the circuit under test. ~~This~~ is sufficiently low to allow measurement of ~~the~~ voltage across a geiger tube while it is ~~in operation~~, which happens to be the primary reason for building the thing in the first place.		This voltmeter is useful for measuring DC voltages without loading down the circuit under test. The input impedance of a regular multimeter can sometimes be too much of a burden for circuits incapable of delivering sufficient current to maintain voltage while taking a reading. Thanks to the gigaohm input impedance, this meter draws only 1 nanoamp per volt from the circuit under test. That is sufficiently low to allow measurement of voltage across a geiger tube while it is operating, which happens to be the primary reason for building the thing in the first place.

	==Can I open it?==		==Can I open it?==

Thomastheo: /* What's in the box */

2017-12-21T11:53:09Z

What's in the box

← Older revision		Revision as of 11:53, 21 December 2017
Line 13:		Line 13:
	==What's in the box==		==What's in the box==

	This is nothing more than a resistive divider and a high impedance voltmeter. The divider is a Dale 1 gigaohm 1.5kv 1% tolerance resistor, and a regular anonymous 100K carbon resistor. Crashjuh supplied a Dynatek 200 millivolt 200 megaohm input impedance panel meter, which is connected across the 100k resistor. Because of the 200mV range, the reading output by the display ''does'' need to be multiplied by 10x.wo		This is nothing more than a resistive divider and a high impedance voltmeter. The divider consists of a Dale 1 gigaohm 1.5kv 1% tolerance resistor, and a regular anonymous 100K carbon resistor. Crashjuh supplied a Dynatek 200 millivolt 200 megaohm input impedance panel meter, which is connected across the 100k resistor. Because of the 200mV range, the reading output by the display ''does'' need to be multiplied by 10x.wo

	==Operating instructions==		==Operating instructions==

Thomastheo: Created page with "{{Project |Name=Gigaohm Voltmeter |Picture=voltmeter.jpg |Omschrijving= High impedance voltmeter |Status=Completed |Contact=thomas }} ==Important Safety Inform..."

2017-12-21T11:51:17Z

Created page with "{{Project |Name=Gigaohm Voltmeter |Picture=voltmeter.jpg |Omschrijving= High impedance voltmeter |Status=Completed |Contact=thomas }} ==Important Safety Inform..."

New page

{{Project
|Name=Gigaohm Voltmeter
|Picture=voltmeter.jpg
|Omschrijving= High impedance voltmeter
|Status=Completed
|Contact=thomas
}}

==Important Safety Information==

This meter is '''only''' designed to be used for measuring '''very low current''' moderate to high voltage supplies. There is no input protection whatsoever other than the gigaohm resistor, which is rated for a maximum of 1500VDC. The banana jacks are not meant for high-voltage high-current applications. The isolation is not adequate for safe operation with power supplies capable of delivering anything more than a tickle's worth of current.

==What's in the box==

This is nothing more than a resistive divider and a high impedance voltmeter. The divider is a Dale 1 gigaohm 1.5kv 1% tolerance resistor, and a regular anonymous 100K carbon resistor. Crashjuh supplied a Dynatek 200 millivolt 200 megaohm input impedance panel meter, which is connected across the 100k resistor. Because of the 200mV range, the reading output by the display ''does'' need to be multiplied by 10x.wo

==Operating instructions==

Connect circuit to meter with banana jacks. Turn on meter. Cross fingers. Keep in mind that the banana jacks (and cables) are most likely not rated for the voltages you are using them at, so suspend them off and away from conductive surfaces. Keep in mind that this is a high impedance device, and that whatever you are connecting it to is most likely also a high impedance circuit; Long cables can couple in a lot of noise. To minimize this problem I cobbled together a couple of really short banana-crocodile cables.

==Why==

This voltmeter is useful for measuring DC voltages without loading down the circuit under test. The input impedance of a regular multimeter can sometimes be too much of a burden for circuits incapable of delivering sufficient current to maintain voltage while taking a reading. By using a voltage divider with ridiculous values of 1 gigaohm, the meter draws only 1 nanoamp per volt from the circuit under test. This is sufficiently low to allow measurement of the voltage across a geiger tube while it is in operation, which happens to be the primary reason for building the thing in the first place.

==Can I open it?==

No. There is a gigaohm resistor inside, and it does not like finger grease, Mate spray, or sideways glances. The battery should last forever, provided you turn it off after use.

==It doesn't work==

Put it on my Samla (thomas), and let me know. Thanks!