Digital Timer with photogate

Digital timer with photogates (Photogate timer) is a equipment for measuring time through photogates.

- Simple, neat, easy to use

- Display: Large LED 0.8inch,

- Unit: s, ms. Automatically switch the scale

- Resolution: 0.1ms

-  Mode: Timer, Period, count. 6 modes are printed in top of box

-  Input: 2 photogates and 1 electromagnet. 

- Delay time compensation

Including: photogate timer, 2 photogates and holder.

Timer with photogate set: Including two photogate with rod

Photogate timer: large display

Photogate timer with instruction

Photogate timer rear: 1 jack for electromagnet and 2 jacks for photogates

Operating Manual

DIGITAL TIMER

This tiimer has 6 modes, capable of attaching 2 photogates and 1 electromagnet

Switch modes by pressing Mode button below: 

(Photogate timer: Change Mode)

Mode 1: Measuring time through each photogate t₁ and t₂.

Suitable for instantaneous velocity measurement experiments.

Set up and operating:

• Attach 2 photogates to port 1 and 2: If the experiment needs only one photogate, we attach 1 photogate. It is not necessary to plug in 2 photogates at the same time
• Turn on the timer: The default status is Mode 1 when the device is turned on
• Start measuring: Press the START / STOP button. Number "1" runs along the screen like the clip below, then start to move objects through the photogates. After finishing the motion, press the START / STOP button again. The results will be displayed on the timer.

(Photogate timer: Mode 1)

• Reading:

+ Timer display - -1- in 2s, then display time measured: 038.1ms: the time the object passes through photogate 1 is t₁  = 38.1ms

+ Timer display - -2- in 2s, then display time measured: 045.5ms: the time the object passes through photogate 2 is t₂  = 45.5ms

+ Value "045.5"  paused for a longer time and then display datas "038.1",  "045.5" again sequentially: That mean "045.5" is the last data measured by digital timer. 

• To perform the measurement again, press START/STOP (dont press Mode button)

Mode 2: Measure the amount of time the object moves from photogate 1 to photogate 2 (t_1-2), from photogate 2 coming back to photogate 1 (t_2-1),  time from photogate 2 coming back to photogate 2 (t_2-2), time from photogate 1 coming back to photogate 1 (t_1-1).

Suitable for average velocity measurement experiments.

Set up and operating:

• Attach 2 photogates to port 1 and 2.
• Turn on the timer, switch to Mode 2
• Measuring: Press START/STOP. Number "2" runs along the screen like the clip below, then start to move objects through the photogates. After finishing the motion, press the START / STOP button again. The results will be displayed on the timer.

(Photogate timer: Mode 2)

• Reading:

+ The Timer displays "1--2" for 2s and then displays the value: 697.6: it means that the time it takes for the object to go from photogate 1 to photogate 2 is t_1-2  = 697.6ms.

• To perform the measurement again, press START/STOP (see the clip above)

Mode 3: Measuring time from electromagnet to photogate 1 (t_0-1), time through photogate 1 (t₁), Measuring time from photogate 1 to photogate 2 (t_1-2) and time through photogate 2 (t₂).

Suitable for free-fall experiments, motion on an inclined plane, and evenly variable linear motion.

Set up and operating:

• Attach 2 photogates to port 1 and 2. Attach electromagnet to port 0. 
• Turn on the timer, switch to Mode 3

• Attach steel object to electromagnet. Magnet will attract steel object. 

• Measuring: Press START/STOP. Number "2" runs along the screen like the clip below, then start to move objects through the photogates. After finishing the motion, press the START / STOP button again. The results will be displayed on the timer.

( Timer with Photogate: Mode 3)

• Reading:

+ The Timer displays "0--1" for 2s and then displays the value: 565.1: it means that the time it takes for the object to go from electromagnet to photogate 1 is t_0-1  = 565.1ms.

+ The Timer displays "--1-" for 2s and then displays the value: 035.3: the time the object passes through photogate 1 is t₁  = 35.3ms

+ The Timer displays "1--2" for 2s and then displays the value: 659.6: it means that the time it takes for the object to go from photogate 1 to photogate 2 is t_1-2  = 659.6ms.

+ The Timer displays "--2-" for 2s and then displays the value: 037.2: the time the object passes through photogate 2 is t₂  = 37.2ms

Mode 4: Measuring period 

Suitable for oscillating measurements of simple pendulum, spring pendulum, rotating motion.

Set up and operating:

• Attach one photogate to port 1 or 2.
• Turn on the timer, switch to Mode 4

• Pull the pendulum into position so that the ball covers the photogate eye. Release the ball to oscillate.

• Measuring: Press START/STOP. Number "4" runs along the screen like the clip below. The digital timer begins to show the cycle of the pendulum. Press the START / STOP button to stop the measurement.

(Timer with Photogate: Mode 4)

• Readings:

+ The Timer displays "-0--" , then displays the value: 1.476: it is the first period of pendulum T₀  = 1.476s.

+ The Timer displays "-1--" , then displays the value: 1.487: it is the second period of pendulum T₁  = 1.487s.

+ The Timer displays "-2--" , then displays the value: 1.483: it is the third period of pendulum T₂  = 1.483s.

+ The Timer displays "-3--" , then displays the value: 1.483: it is the fourth period of pendulum T₃  = 1.483s.

.....................

+ The Timer displays "-9--" , then displays the value: 1.481: it is the first nineth of pendulum T₉  = 1.481s.

+ The Timer displays "-A--" , then displays the value: 1.482: it is the average period of pendulum TA  = 1.482s.

This is the average of the first 10 cycles of the pendulum. This value "1.482"  will stop for a bit longer and then show cycles from 0 - 9 respectively

Mode 5: Counting and time total.

Suitable for counting experiments and calculating the average oscillation period of the pendulum.

Set up and operating:

• Attach one photogate to port 1 or port 2. Maybe attach 2 photogates at the same time
• Turn on the timer, switch to Mode 5

• Measuring: Press START/STOP. Number "5" runs along the screen like the clip below.  Move objects back and forth through the photogate. Timer will count. Press START/STOP to stop.  The timer will count the total number of times the object has pased through the photogate (value "-0--" =15) and the total time ("-1--" = 21.03s). 

(Timer with Photogate: Mode 5)

• Calculate average period of pendulum:

+ Release the ball to oscillate. Press Start/Stop (watch clip above at 54th second)

+ Press Start/Stop when count to 11.

+ Timer show: 11 period in 14.86s.

+ So average period: 1.486s

Mode 6: Compensation the delay of electromagnet. 

If the electromagnet has a large residual magnetic field, it will take a short time for the magnet to release the ball when the Start / Stop button is pressed.

This delay can be overcome by subtracting the time delay in the measured results. We carefully check the delay time and then switch the clock to mode 6 as in the clip below.

( Timer with Photogate: Daley compansation)

Press to mode 6, digital timer shows current time the timer is minus. According to the clip above, when you press to mode 6, the clock displays 000.9ms, which means that the t_0-1 value in mode 3 has been subtracted 0.9ms.

If we want the value t_0-1 to subtract 16.1ms, we press Start / Stop until the clock shows 016.1 then press Start / Stop again to stop.

Error:

When you press Start / Stop to show results, but the timer displays as shown picture below, the signal has not been collected. So please check:

+ The photogate is not plugged in or the plug is not tight or the plug is rusted.

+ The moving object has not been passed through the photogate eye: Adjust the moving object again

+ Broken photogate: Try by switch to Mode 5, then press Start / Stop, then move your finger to see if it counts. If not, replace another photogate.

Time counter : No signal received