Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Regarding ceramic capacitors via transistor

Status
Not open for further replies.

Electronically

Newbie level 1
Joined
Apr 26, 2015
Messages
1
Helped
0
Reputation
0
Reaction score
0
Trophy points
1
Activity points
11
Hi all ,I have a question ,first off all I'll explain ,I don't have a ceramic capacitor of a 4.7pf .which this ceramic capacitor sits parallel with transistor emitter and collector .is there anything else that can be used I don't have anything less than the value above .i was thinking of doing two 10pf ceramic capacitors in series which would give me 5p .but problem I have there is I don't fancy doing it in series .if anyone could give me tips on that would be ever so great full thanks
 

Audioguru

Advanced Member level 5
Joined
Jan 19, 2008
Messages
9,217
Helped
2,129
Reputation
4,252
Reaction score
1,957
Trophy points
1,393
Location
Toronto area of Canada
Activity points
57,912
You can use a "gimmick capacitor" which is two insulated wires twisted together. Maybe each wire about 1" (2.54m) long?
4.7pf is almost nothing but is used at high RF frequencies like in the oscillator for an FM transmitter.
 

Vbase

Full Member level 6
Joined
Apr 7, 2015
Messages
367
Helped
74
Reputation
148
Reaction score
72
Trophy points
28
Activity points
1,997
Using your cutter cut the top half of 10pF and you are left with 5pF.
 

BradtheRad

Super Moderator
Staff member
Joined
Apr 1, 2011
Messages
14,002
Helped
2,789
Reputation
5,576
Reaction score
2,696
Trophy points
1,393
Location
Minneapolis, Minnesota, USA
Activity points
104,443
Using your cutter cut the top half of 10pF and you are left with 5pF.

At first this looks like a prankish remark, but with a little thought I realize this really will work.

If we're talking about a little 10pF ceramic capacitor, then it has two plates close together. You can reduce the Farad value by reducing the area of the plates.
 

SunnySkyguy

Advanced Member level 5
Joined
Sep 26, 2007
Messages
6,743
Helped
1,675
Reputation
3,348
Reaction score
1,644
Trophy points
1,413
Location
Richmond Hill, ON, Canada
Activity points
50,732
for prototypes we used to sand the top off a ceramic disk on fine wet-dry sand paper and grind off as much as 50% pF but will get brittle and weak.
Cap for CE is often critical for tuning oscillators. It should also be a COG or NP0 type cap.

If not using SMD

remember to keep your leads short.
 

Status
Not open for further replies.

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top