Analog to TTL converter
Cliff Kaminsky
output might range between -0.9 to -0.3 volts sinusoidally. I want to buy or
build a circuit that will convert this sinusoid into a TTL pulse to use as a
digital trigger. Could you please e-mail or fax me a source for such an
item, or e-mail or fax me a schematic? You will have my eternal gratitude
(and possibly a couple of bucks.) My fax number is (810) 597-0254. Thank
you.
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Cliff Kaminsky Mechanical Engineer
cli...@oeonline.com Hughes Aircraft Company
kami...@kocrsv01.delcoelect.com Guitar and keyboard
cskam...@ccgate.hac.com Fingers
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Mark Johnson
> I have a low frequency (0.5-1.5 Hz) signal that has a DC offset
> such that the output might range between -0.9 to -0.3 volts
> sinusoidally. I want to buy or build a circuit that will
> convert this sinusoid into a TTL pulse to use as a digital
> trigger. Could you please e-mail or fax me a source for
> such an item, or e-mail or fax me a schematic?
>
One brute force solution uses the venerable LM-339 chip.
(If you're a power scrooge you could consider the LP-339,
a pin compatible replacement.)
+5.0 Volts +5.0 Volts
| |
| |
| |
+-----+ |
| R1 | +-----+
C1 |100K | |\ | R3 |
100 uF | | | \ | 1K |
- | | + +-----+ | \ | |
| | | | \ +-----+
SINEWAVE --| |-----o----------------| 5 \ |
INPUT | | | | | \ |
| | +-----+ | | 2 >--------o-------> TTL
| R3 | | | / output
|330K | o-----| 4 /
| | | | /
+-----+ | | / IC1: LM-339 or LP-339
| | | / +5V power to pin 3
| | |/ GND to pin 12
o----------o
| |
C2 | + +-----+
------- | R2 |
------- |100K |
10 uF | - | |
| +-----+
| |
| |
GND GND
Bad ASCII drawing notes: a "solder dot" is rendered as "o".
Notice that pin 5 of the IC is NOT shorted to pin 4
(that's a "crossunder" on the diagram). Pin 5 connects
to the junction of C1 and R3. Pin 4 connects to the
junction of (R1, R2, R3, and C2).
Phil Maness
>Bad ASCII drawing notes: a "solder dot" is rendered as "o".
Pretty impressive drawing !
Brian Vicente
>In article <MJOHNSON.95...@netcom2.netcom.com>, mjoh...@netcom2.netcom.com (Mark Johnson) writes:
>> In article <DD5n9...@oeonline.oeonline.com> cli...@oeonline.com (Cliff Kaminsky) writes:
>> > I have a low frequency (0.5-1.5 Hz) signal that has a DC offset
>> > such that the output might range between -0.9 to -0.3 volts
>> > sinusoidally. I want to buy or build a circuit that will
>> > convert this sinusoid into a TTL pulse to use as a digital
>> > trigger. Could you please e-mail or fax me a source for
>> > such an item, or e-mail or fax me a schematic?
>> >
>Why ac coupling? I recommend the following. (I have edited the schematic)
>You would probably want to have some hysterisis. Try a 1M resistor from
>pin 2 of the op amp to the "+" input. I'm not sure on the LM339 whether this
>is pin 4 or 5. Also, I am more familiar with the LM193 (dual)
>op amps. These are low power and will run off 5 volts. In these devices, the
>negative input is always closest to the output.
>>
>> One brute force solution uses the venerable LM-339 chip.
>> (If you're a power scrooge you could consider the LP-339,
>> a pin compatible replacement.)
>>
>> +5.0 Volts +5.0 Volts
>> | |
>> _________o |
>> | | |
>> | +-----+ |
>> | | R1 | +-----+
>> R5 |100K | |\ | R3 |
>> 100k | | | \ | 1K |
>> | +-----+ | \ | |
>> | | | \ +-----+
>> SINEWAVE -- R4 -----o---------------| 5 \ |
>> INPUT 110k | | \ |
>> | | 2 >--------o-------> TTL
>> | | / output
>> o-----| 4 /
>> | | /
>> | | / IC1: LM-339 or LP-339
>> | | / +5V power to pin 3
>> | |/ GND to pin 12
>> o----------o
>> | |
>> C2 | + +-----+
>> ------- | R2 |
>> ------- |100K |
>> 10 uF | - | |
>> | +-----+
>> |__________o
>> |
>> GND
>>
>>
>> Bad ASCII drawing notes: a "solder dot" is rendered as "o".
>> Notice that pin 5 of the IC is NOT shorted to pin 4
>> (that's a "crossunder" on the diagram). Pin 5 connects
>> to the junction of C1 and R3. Pin 4 connects to the
>> junction of (R1, R2, R3, and C2).
>--
>Mike McDermott c22...@kopt0002.delcoelect.com
>(Hey, I'm just this guy, you know?)
Can somebody put nfo about reading these drawings. Matbe it's just
hard on my eyes or something but I can't see what it is or
represents.Thanks in advance.
Jason Patrick White
: Can somebody put nfo about reading these drawings. Matbe it's just
: hard on my eyes or something but I can't see what it is or
: represents.Thanks in advance.
Perhaps you are using a non-proportional font to view the picture... it is
an ascii representation of a schematic. All the slashes should form a
triangular op-amp symbol.
If all else fails, stand back and squint! : )
- Jason
---
Jason White
Support Systems Developer
WorldCom: The International Network for Lotus Notes
Mike McDermott
Peter Hesketh
br...@ewald.mbi.ucla.edu "Brian Vicente" writes:
>
> Can somebody put nfo about reading these drawings. Matbe it's just
> hard on my eyes or something but I can't see what it is or
> represents.Thanks in advance.
I don't see any way they can be made simpler! Give me an example of the first
thing you don't understand. -- pbh
--
Peter Hesketh
"Pas de lieu Rhone que nous"