CGS Serge voltage controlled gain cell (view source)
Revision as of 23:23, 11 January 2019
, 5 years agono edit summary
No edit summary |
No edit summary |
||
Line 8:
Note that the orientation for the transistors on the overlay is for BC547B and BC557B transistors. The pinout of modern PNXXXX devices is usually the reverse of what was used with the 2NXXXX devices. PN4250 (use instead of BC557B) would need to be installed backwards with respect to the "D" on the overlay. 2N5089 (use instead of BC547B) has variant pinouts depending on manufacturer. Check with the datasheet for the brand you have purchased.
Like types of transistors must be matched, more so with the NPN pair, as the trimpot can deal with some degree of mismatch in the PNP pair. See one of the other online resources for transistor matching, or follow the [[CGS
Before you start assembly, check the board for etching faults. Look for any shorts between tracks, or open circuits due to over etching. Take this opportunity to sand the edges of the board if needed, removing any splinters or rough edges.
| |||