1.5V square wave generator experiment

http://wp.me/ph3BR-PG

這個是抄來的, 當時忘了做筆記

1

 

Parts:

R1____________560K   1/4W Resistor
R2____________680R   1/4W Resistor
R3______________2K2  1/4W Resistor
R4____________150K   1/4W Resistor

C1_____________12nF   63V Polyester Capacitor
C2______________1n2   63V Polyester Capacitor
C3____________120pF   63V Polystyrene or ceramic Capacitor
C4,C5__________10µF   25V Electrolytic Capacitors

Q1,Q2________BC549C  25V 100mA NPN High-gain Low-noise Transistors

SW1____________SPST  Slider Switch
SW2____________1 pole 3 ways Rotary Switch

B1_____________1.5V Battery (AA or AAA cell etc.)

 

Comments:

This simple circuit generates a good and stable 1V peak-to-peak square wave at 100Hz, 1KHz and 10KHz using a single 1.5V cell as power supply.
An useful feature of this circuit is that frequency changes can be obtained by switching only one capacitor at a time.
Current consumption is about 600µA.

Notes:

  • If a precise 50% duty-cycle is needed, trim R1 and monitor the output wave form by means of an oscilloscope.
  • A good 500mV peak-to-peak square wave is provided even at 1V supply.  (TBC  ????)

 

原文是這個

http://www.redcircuits.com/Page74.htm

nEO_IMG_DSCF3269 nEO_IMG_DSCF3268

DSCF3307 KENWOOD-CS-4025 示波器 trace drift down slowly

注意觀察, 借用人家的示波器, 光跡慢慢往下移, 不到一分鐘時間, 應該是內部有些電容老化了, 沒空幫人家修理

http://youtu.be/ZYFYpCUkT3Q

KENWOOD-CS-4025 示波器沒有高壓產生, 沒有光跡顯示

http://wp.me/ph3BR-v4

生平第一次修理CRT示波器, 以前玩過 DIY 修理 CRT 電視機.

對照圖紙, 測過供電電壓, 有光跡顯示和無光跡顯示的是有分別, 但是好像不大.

原來兩台都有顯示, 只是毛刺波形之類的, 一陣子後, 其中一台就沒顯示, 聞到很輕的高溫產生的味道, Continue reading “KENWOOD-CS-4025 示波器沒有高壓產生, 沒有光跡顯示"