Humble Electronics #010 - PAD - 234 Analog/Digital Trainer 01.2 (Summer 2023)

 This post will cover the power outputs and the switches.

I'll start with the power binding posts. The +5V post is putting out 4.84V. The LED is connected to that post through the breadboard. The +12V post is not connected to the breadboard and is supplying 12V while the -12V post is delivering -11.82V.

 

The variable voltage tie points are next. The positive Voltage supply outputs 1.25V minimum and 21.7V maximum. That's more than the 15V the manual gave. Similarly, the negative Voltage supply outputs a range from -1.3V to -21.7V.

I checked the voltages on the tie points on one of the switches. It output 0V on low and 4.84V on high. I then connected a different one to an LED without a ground connection to check its operation and it worked. I have checked the other ones this past summer & they all worked.

 

 

I recorded the switch bounce on the oscilloscope. These switches are not de-bounced as seen below. The oscilloscope images were saved to a USB stick directly from the oscilloscope and transferred onto the computer. It looks like the bouncing stops within 1.4mS. The falling edge went down to ground at 1.58uS with no bouncing.

 

I tested the pulse switches and recorded the bounce on the oscilloscope. Each tie block is at 5V and 0V, for 1 & 0 block respectively, until the momentary switch is flipped. Then the voltage changes to the other voltage. I'm happy with the denouncing on these switches and they have a nice springy feel. The rising and falling edge happen in 410nS.

 

 

 

Finally we'll look at the AC output. I used two probes to show each end to the center tap so we can see the 180 degree offset. I then connected the oscilloscope to one line and the center tap, then across both lines.

 

Probe connected with each 6.3VAC to center. It is measuring 20Vpp on each supply at 60.2Hz.

 

One Probe connected between one 6.3VAC to center. The frequency is now reading 59.9Hz and did vary a tiny bit while running.

One probe connected to each 6.3VAC output as shown below. It is reading 38.8Vpp at 59.9Hz.

All those values on the AC and the variable DC outputs are higher than reported in the manual. I'm glad I investigated it before I used it. I will likely open this thing up and see if there has been any "upgrading" to it before I bought it. I will not show the inside, in respect to the manufacturer, but I will make a post if I find anything not on the schematic.

Next post will have the clock and generator outputs on the oscilloscope. 

Happy Making!

Michelle