Hi all,

Thanks for the help on the switches. I think I will use Mike Keitz's
suggestion (given to me in a private reply), to use a DPDT switch (which I
think will fit into the hole already drilled in the case).

The actual application is a frequency counter and function gen in one case.
You can switch the source of the freq. counter between the ext. input and
the function gen. Because the function gen needs to operate even when the
counter is connected, I cannot simply ground the function gen to isolate it
from the counter. SO, the DPDT switch will allow me to connect the gen to
the counter indirectly,and ground the indirect line when not in use.

The frequency range is from 3Hz to 16Mhz. I can't work in a 50ohm
environment because the amp input needs to be high impedance, so that it
won't affect the external circuit that it is measuring. The function gen
output is 50 ohms, however.

BTW, to those who remember the thread on using 7404's as linear amplifiers,
which was months ago, I finally did get it to work by using 74HCU04's,so
yes,the answer was unbuffered gates,in addition to NOT using gates with
adjacent pins (i.e., when using more than one on the same chip, skip a gate
inbetween,and ground its input).

When I have some pictures and schematics to show, I will put it up on my
web page. Originally, I planned on including a dual channel power supply in
the same case. I ended up building it separately,and it is also completed
and should be documented on my page in the not-too-distance future.

Thanks to all,

Sean



|
| Sean Breheny
| Amateur Radio Callsign: KA3YXM
| Electrical Engineering Student
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