Test Kit Group Buy: Stackable Voltmeter Plugs + Lamp

[nigelmercier]

digital volt meter. They take so little current that they give a normal reading despite there being a bad connection. A test lamp. ( a small bulb on a couple of leads ) is what you need ... or even the meter with a small bulb in parallel

You have just reminded me that I plan to make up a lead with stackable 4mm banana plugs connected to a 24V lamp.

I'm just about to place an order for these, and it occurred to me that others may be interested.

NOTE THAT THE LAMP IS 24V, IT WILL WORK BETTER ON 12V

http://cpc.farnell.com/IN05038
http://cpc.farnell.com/IN05039
http://cpc.farnell.com/CP03122

Lamp sockets (if required) are available here: http://r.ebay.com/LFz1ZZ

The plan is to cut the leads in half and solder to the bulb, possibly with clear heat-shrink over.

Total price for 25cm red and black leads (as above but cut in half, so with a single plug), plus the 24V lamp is about £1.50 plus VAT and P&P at cost.

Please reply below if you want a kit of these parts (not PM yet).

 

[nigelmercier]

No replies to this, but here is the result.
This is the digital voltmeter showing the voltage with no load (ignore the discrepancy in the voltages, PSU not calibrated):

Here is exactly the same voltage setting, but with the lamp connected.

As you can see, it is vital to put a load on a meter when checking a suspect voltage.

 

[awol]

I think RTFM is in order! Pic 1 is in constant voltage mode; Pic 2 is in constant current mode.

 

[lw395]

I think RTFM is in order! Pic 1 is in constant voltage mode; Pic 2 is in constant current mode.

That's the point, the controls of the PSU don't need to be touched, to change it from CV to CC, just load it.
It's mimicking a voltage source with a non-zero output impedance.

 

[awol]

I must be missing the point. Pic 2 PSU output voltage is being limited by the load. Use an unlimited current source, like a battery and the voltage stays the same. Stick a resistor (bad connection simulator) into one of the PSU wires and the point would be made.

 

[nigelmercier]

It's mimicking a voltage source with a non-zero output impedance.

Quite, easiest way to simulate a bad connection.