• Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

Need TTL Cookbook page 171 & 172. 555 timer 2N3055 vintage Electric Fence Charger

gary350

Well-Known Member
Thread starter #1
My TTL Coolbook is missing page 171 and 172 does anyone have a copy of those 2 pages. ?

I need a 60 year old electric fence charger to keep 4 cats and 1 dog out of the garden. The new modern electric fence charges are continuous ON that can kill small animals. I already murdered a black bird & squirrel. I need an 60 year old vintage 2 second relay type fence charger that sends 1 spark every 2 seconds.

I am sure I read in my TTL book duty cycle of a 555 can be set 5% of the total time. If R1 & R2 plus capacitor are set for 2 seconds then 5% of that is 1/10th of a second. If I can send a voltage pulse to the auto transformer it will send out a HV spark every 2 seconds.

I have this circuit already built from 40 years ago it has a variable resistor to adjust Hz from 1 Hz to much higher. I have learned from experiments output is best at a low Hz. I need to change my circuit to 5% high output every 2 seconds.

I started reading my TTL book it wants me to see electric circuit probably on page 171 or 172 but that page is gone. Once I change the circuit then test it I might learn it works better at .2 seconds or . 3 seconds. Book says duty cycle can be 99.9% = .02 second.

High time needs to be .1 second. Low time needs to be 1.95 seconds.

100_2825.JPG
 
Last edited:

AnalogKid

Well-Known Member
#3
You are half-way there without the book.

0. Change to the CMOS version: LMC555

1. The emitter arrow on the 3055 points the other way.

2. Insert a 150 ohm resistor between 555 pin 3 and the 3055 base. This limits the base current to something the 555 can supply safely.

3. 555 power is pin 8. also connect pin 4 to Vcc.

That was the easy part. The standard 555 timing circuit cannot produce an output duty cycle (ratio of up time to down time) less than 50%, while you want 5%. There are many examples of how to get around this on the innergoogle and on this site. Short form, you still need only one timing capacitor. But besides the two timing resistors, you need two small signal diodes (1N914, 1N4148, etc.).

ak
 
Last edited:

Pommie

Well-Known Member
Most Helpful Member
#7
Just looked up on the shelf to see where my copy was. Looks like I probably threw it out last time I moved homes. The oldest book up there is Hughes Electrical Technology Fifth edition - wonder why I kept that one.

Mike.
 

gary350

Well-Known Member
Thread starter #8
You are half-way there without the book.

0. Change to the CMOS version: LMC555

1. The emitter arrow on the 3055 points the other way.

2. Insert a 150 ohm resistor between 555 pin 3 and the 3055 base. This limits the base current to something the 555 can supply safely.

3. 555 power is pin 8. also connect pin 4 to Vcc.

That was the easy part. The standard 555 timing circuit cannot produce an output duty cycle (ratio of up time to down time) less than 50%, while you want 5%. There are many examples of how to get around this on the innergoogle and on this site. Short form, you still need only one timing capacitor. But besides the two timing resistors, you need two small signal diodes (1N914, 1N4148, etc.).

ak

I read what is left of my TTL book it looks like 555 will do 95% high but not 95% low so it will not do what I want.

I printed page 171 and 172.
 
Last edited:

Nigel Goodwin

Super Moderator
Most Helpful Member
#12
I need a 60 year old electric fence charger to keep 4 cats and 1 dog out of the garden. The new modern electric fence charges are continuous ON that can kill small animals. I already murdered a black bird & squirrel. I need an 60 year old vintage 2 second relay type fence charger that sends 1 spark every 2 seconds.
As usual your assumptions are completely wrong, electric fences are never continuously ON, both because it would be illegal, and (more importantly) it would greatly reduce battery life. Electric fences are designed to stop cows, horses etc. - not tiny animals, I'm not surprised one would kill small animals, however their normal usage would mean that it's pretty well impossible for them to affect small animals.

A simple physical fence would keep the dog out, but you're not going to stop cats, not even with an electric fence.
 

gary350

Well-Known Member
Thread starter #13
As usual your assumptions are completely wrong, electric fences are never continuously ON, both because it would be illegal, and (more importantly) it would greatly reduce battery life. Electric fences are designed to stop cows, horses etc. - not tiny animals, I'm not surprised one would kill small animals, however their normal usage would mean that it's pretty well impossible for them to affect small animals.

A simple physical fence would keep the dog out, but you're not going to stop cats, not even with an electric fence.
The electric fence charger that I bought to experiment with is 120 VAC it seems to be a high voltage transformer it makes a continuous spark. My grandfather had a battery fence charger with a rotating clock wheel that went, click..........................click........................click..........................click..........................click. It worked like a car ignition coil every time contacts close then open it produces 1 high voltage spark. I should be able to build a fence charger with a 555 timer identical to the old vintage fence charges to make 1 spark every 2 seconds.

Simulator is cool but I'm not sure what I am looking at. http://tinyurl.com/yxn35mp3 Bottom right corner parts values change depending where mouse pointer is. R1=44 R2=955 or R1=341 R2=658. After doing the math i see 44 and 955 are correct. I still don't know capacitor value? Math shows cap of .15uf high time is .1 second
 
Last edited:

unclejed613

Well-Known Member
Most Helpful Member
#15

crutschow

Well-Known Member
Most Helpful Member
#16
Here's the LTspice simulation of AK's 555 circuit in post #9 with fixed resistors to give the desired duty-cycle of 0.1s ON with a 2s period:

1553011790334.png

Edit: Below's a modified circuit with only one diode.
The main advantage is that the timing circuit is not connected to the output, as in the above circuit, so any output loading has no effect on the timing.

1553028510189.png
 
Last edited:

audioguru

Well-Known Member
Most Helpful Member
#17
The TV high voltage transformer or the car ignition coil are shown wrongly in the first post as a tapped coil without any DC power. Then they will do nothing.
 

gary350

Well-Known Member
Thread starter #18
This is my circuit. I have not decided if I am doing solar power or 12vdc power supply. Solar is 23v no load, 18v with load. I assume I can use a 7815 and 7812 to get 12v. I have a 12vdc power supply 1.8a which will be much easier than solar but not sure 1.8a is enough. If 555 pulse is .1 second a capacitor can be charging up for .9 seconds for the next pulse. I need to order the BD139 transistor from Colorado. I have a lot of transistors to choose from but I'm not motivated to spend 3 hours looking at datasheet to find a substitute transistor. I drew the circuit from the datasheet I can change resistors to get the pulse that works best .1 second every 1 or 2 seconds.

I have TV HV transformer and ignition coil to experiment with to see which works best.

I use to have a dozen 2N3055s but I can not find any of them?

100_2861.JPG

100_2860.JPG

100_2859.JPG

100_2862.JPG
 

crutschow

Well-Known Member
Most Helpful Member
#19
Why do you have two regulators in series?
One 12V regulator should be sufficient.

If that capacitor on pin 2 is 100nF, you wouldn't be able to get a 2s period.
That should be around 10uF.
 

Latest threads

EE World Online Articles

Loading

 
Top