Can I Use an SCR Dimmer for My Old Phone Ringer Project?

  • Thread starter Thread starter abodell
  • Start date Start date
  • Tags Tags
    Project
AI Thread Summary
An old phone from the 1950s requires an 80V ringer voltage at 20-25 Hz for ringing. A variac can adjust the voltage, but frequency control is also needed. An SCR dimmer can be utilized, triggered by a microprocessor like the 16F684, which counts AC cycles to adjust the frequency. By delaying the trigger appropriately within the AC cycle, the desired 80 volts RMS can be achieved. This method offers a cost-effective solution for the project.
abodell
Messages
1
Reaction score
0
Hello All, I am working on a project to get a old phone (from the 50's) to ring. The problem that I have is ringer voltage is 80V @ 20-25 Hrtz. I am trying to come up with a really cheap way to achieve this. I was thinking of getting a variac to set the voltage at 80V but I would still need a way to alter the frequency. Any help will be much appreciated!
 
Engineering news on Phys.org
Get an SCR dimmer. Arrange it to be triggered by a microprocessor (like a 16F684) where it counts AC cycles and triggers on every third one. If you delay the trigger for the right length of time in the AC cycle you will get the 80 volts RMS too.
 

Thread 'Underwater piezoelectric sensor array receive sensitivity'

Hi all I have some confusion about piezoelectrical sensors combination. If i have three acoustic piezoelectrical sensors (with same receive sensitivity in dB ref V/1uPa) placed at specific distance, these sensors receive acoustic signal from a sound source placed at far field distance (Plane Wave) and from broadside. I receive output of these sensors through individual preamplifiers, add them through hardware like summer circuit adder or in software after digitization and in this way got an...
View full post »

Thread 'Following up on the recent thread about Earth Resistance measurements'

I have recently moved into a new (rather ancient) house and had a few trips of my Residual Current breaker. I dug out my old Socket tester which tell me the three pins are correct. But then the Red warning light tells me my socket(s) fail the loop test. I never had this before but my last house had an overhead supply with no Earth from the company. The tester said "get this checked" and the man said the (high but not ridiculous) earth resistance was acceptable. I stuck a new copper earth...
View full post »
Thread 'Beauty of old electrical and measuring things, etc.'

Thread 'Beauty of old electrical and measuring things, etc.'

Even as a kid, I saw beauty in old devices. That made me want to understand how they worked. I had lots of old things that I keep and now reviving. Old things need to work to see the beauty. Here's what I've done so far. Two views of the gadgets shelves and my small work space: Here's a close up look at the meters, gauges and other measuring things: This is what I think of as surface-mount electrical components and wiring. The components are very old and shows how...
View full post »

Similar threads

What is the issue with my boost converter design and how can I fix it?
2
Replies
55
Views
5K
12V DC Motor in Light Fixture with Dimmer & 12V DC to 110V AC Inverter
Replies
21
Views
2K
What voltage/current/power meter do you use in your (hobby) projects?
Replies
2
Views
2K
How does AM broadcasting/receiving work + a project for HS students?
Replies
20
Views
1K
Can I Build a Simple Mobile Phone for My Graduation Project?
Replies
9
Views
3K
How can I design a circuit for my project?
Replies
10
Views
2K
Can I series buck converters to get higher stepdown ratio?
Replies
10
Views
2K
How Can I Efficiently Build a Solar Phone Charger with Nimh and Lipo Batteries?
Replies
5
Views
2K
Understanding Inputs and Outputs for Specific Project
Replies
12
Views
2K
Can Linux Improve ADC Sampling Rate on Intel Galileo Gen 2?
Replies
7
Views
4K

Hot Threads

Recent Insights

Back
Top